Hiroshi Agasa is an inventor and Shinichi's next-door neighbor. He makes his living with a wide number of patents and inventions, including video games (of which the Detective Boys are enthusiastic test players). While many of his inventions are useless or have even damaged his in-house research laboratory, Agasa has been successful enough to live in a large house and even rebuild it when necessary. He has been a friend of Shinichi and Ran since their childhood years.