Haruo Yamashita is a Japanese author born in 1937, best known for creating children's picture books that have been adapted into anime. His most recognized work is the original story Nezumi no Densha, which translates to The Mouse Train.

This story was first published in Japan in 1981 as a picture book by Child Honsha Co., Ltd.. The English edition, titled Seven Little Mice Go to School, was later released in 2011 by North-South Books. The narrative follows a mother mouse who cleverly solves the problem of getting her seven children safely to their first day of school by having them form a mouse train, a journey that involves an encounter with a snake. The illustrations for the book series are consistently provided by artist Kazuo Iwamura.

Yamashita's work serves as the original source material for the anime adaptation Nezumi no Densha～Nanatsu Ko-Nezumi Series 1, a half-hour OAV released in Japan on October 21, 1994. For this production, he is officially credited as the original creator of the story. The anime was directed by Norio Kashima and produced by the animation studio Aubec. The credit for the story is shared, with Yamashita, Kazuo Iwamura, and Genki Fujino listed as screenwriters for the adaptation.

The central themes of Yamashita's known work revolve around family, cooperation, and overcoming small fears, using a cast of young mouse siblings. His significance in the industry lies in creating a enduring children's story that successfully transitioned from a popular picture book to a screen adaptation, demonstrating a common pathway for family-oriented content in Japanese media.