Ishida's teacher at the elementary school. He is a shallow man who finds Nishimiya's presence in the school unfair on the other pupils.
While he was disappointed in Ishida for bullying Nishimiya, he still laughed at the jokes made about her, and once Nishimiya left, he prompted the class to turn Ishida into a scapegoat for all their bullying. He refused to believe Ishida when he claimed he was being bullied too. Years later, Ishida runs into Takeuchi again when looking for locations for the film. Takeuchi says that Ishida has grown into a fine young man and all the bad things in his past have changed Ishida for the better. Mashiba dislikes how Takeuchi talks about Nishimiya and throws his drink into Takeuchi's face, costing them the chance to film at the school, though with Ishida's later hospitalization and Mashiba's apology to him, Takeuchi allows them to shoot anyway.
