TV-Series
Description
Prof. Hiroshi Agasa, commonly called Professor Agasa, is an inventor and engineer who appears throughout the Detective Conan series. His given name, Hiroshi, is written with the characters that also mean "doctor" or "professor," and this coincidence is why nearly everyone knows him by the title Professor rather than by his first name. He lives in a large residence with a laboratory at 2-chome 22-ban, Beika Town, Tokyo, directly next door to the Kudo family home, and some English-language versions of the story render his name as Hershel Agasa.

Agasa is a longtime family friend of the Kudo family and has known Shinichi Kudo and Ran Mouri since their childhood. He attended Teitan Elementary School and later Okuho Middle School, and he completed a doctoral course in the engineering faculty of Toto University, giving him an advanced degree in his field. As a boy in his final year of elementary school, he fell in love with a girl two years younger than him named Fusae Kinoshita. She moved away during the autumn term, and his own family soon relocated from Tokyo to the countryside, but the two never forgot each other, and in later life she became a successful businesswoman as Fusae Campbell Kinoshita, the head of a famous fashion brand. His background also includes a wealthy uncle, Kurisuke Agasa, an accountant who shared his love of gadgets and died many years before the story begins.

Physically, Agasa is an average-sized man with a slightly overweight frame, and he looks considerably older than his actual age. He is only in his early fifties, yet he has a bald crown, silver hair on the sides, thick eyebrows, a mustache, a somewhat bulbous nose, and round glasses, and he is usually dressed in his laboratory attire. His habit of speaking in an old-fashioned, elderly register adds to the impression that he is much older than he really is. Because of his weight, Ai Haibara later puts him on a strict diet, which he frequently tries to avoid by sneaking snacks. He has a special fondness for pasta, particularly the spaghetti served at a restaurant called Colombo, and for tomato juice.

In personality, Agasa is jovial, caring, outgoing, and patient. He has many friends in his community, a fact that proves useful because he passes Conan and Ai Haibara off as the children of friends and acquaintances whenever their backgrounds need explaining. He is very proud of his inventions, enjoys the company of children, and behaves in a distinctly paternal way toward the younger characters around him, even though he has never married. He is also well known for his love of puns and riddle-style jokes, which he regularly presents to the children to their mixed amusement and exasperation. Beneath his playful and sometimes absent-minded manner, he is highly intelligent, cautious, and dependable, and he often acts as the voice of reason who holds the children back from walking into danger.

Agasa's main motivation is to support Shinichi Kudo after the teenage detective is shrunk into a child's body by the experimental poison APTX 4869 developed by the Black Organization. Agasa is the first person to learn that Conan Edogawa is actually Shinichi, and he immediately advises the boy to keep his identity secret, warning that exposure would put him and everyone around him at risk. He then helps construct Conan's new identity, suggests that Conan move in with the Mouri family, arranges his enrollment at Teitan Elementary School, and builds the special gadgets that allow Conan to continue solving cases undetected. These include the voice-changing bowtie, the power-enhancing kick shoes, the stun-gun wristwatch, the criminal tracking glasses, and the turbo engine skateboard. He also creates the Detective Boys' communication badges and flashlight watches.

His role in the story deepens when Shiho Miyano, the scientist who created the poison, escapes from the Black Organization and collapses near his front door. Agasa takes her in, learns her true identity, protects her from danger, and gives her the new name Ai Haibara, letting her live in his home and attend the same elementary school. He also reveals the secret of Shinichi's condition to Shinichi's parents, Yusaku and Yukiko Kudo. From that point on, he serves as a trusted confidant, a technical support specialist, and a surrogate guardian for both Conan and Haibara, and he becomes one of very few characters who know the hidden identities of several major figures in the story. He is also the person Shinichi relies on for difficult information gathering, particularly when Conan needs access to restricted foreign websites and membership-only databases that an elementary school student could not plausibly use on his own.

Around the Detective Boys, Agasa acts as their unofficial supervisor, advisor, and driver, transporting them to campsites, fishing trips, ski resorts, and other outings in his old yellow Volkswagen Beetle, a car that is notably unreliable and prone to breaking down at the worst moments. Many of these excursions turn into criminal cases, and Agasa frequently ends up assisting the children with their investigations. On occasions when Conan forgets to bring his stun-gun watch, Agasa takes on the role of the detective who delivers the final deduction aloud while Conan feeds him the reasoning from a hidden position, and police officers sometimes praise him as a great detective, which visibly pleases him. He once even boasted to the children that he taught Shinichi everything he knows about detective work.

Over the course of the story, Agasa develops from a friendly neighbor and eccentric inventor into an essential figure in the quiet struggle against the Black Organization. He does not confront the organization directly, but he participates actively in planning, protects those who have escaped from it, and contributes his technology to key operations, including the carefully arranged staged death of an ally through a specially made device. His inventions have been recognized beyond his own circle: they have been used at official events, a public security officer has praised his equipment as rivaling that of a major intelligence agency, and other specialists have admired the performance of his listening devices. At the same time, many of his creations are strange or impractical, such as a portable fax machine disguised as a lunchbox and various household robots, and his long-held dream of becoming rich through his inventions has not come true. He is also remarkably lucky when it comes to winning food vouchers and prize tickets, a knack that often lets him treat the children to meals and activities.

His development is most clearly shown through his relationships. As a bachelor, he becomes a father-like figure to Haibara, who in turn watches over his health and keeps his diet under control, and he becomes a dependable grandfather-like presence for the Detective Boys, who trust him completely even as they tease him. For Conan, Agasa is the one adult who knows everything and never wavers in his support, providing both the tools for each case and a safe place to think and plan. In essence, he is the quiet foundation of the main character's continued fight against the Black Organization: a gifted inventor, a loyal friend, and a warm guardian whose home becomes a refuge for people who have lost their original lives.