Tanabe-sensei appears to be a middle-aged man. He has short black hair, which he keeps slightly spiked upwards, and very small black pupils. He has a very short mustache, which he appears to keep trimmed. In school, he is almost always seen wearing a black tracksuit, with the only exception being during the entrance ceremony, in which he wore a suit and tie.
Tanabe-sensei is very strict with his students, and has a very low tolerance for misbehavior and insubordination. While he yells at almost all of his students, he is especially harsh on Nishikata due to his strange mannerisms and his constant contests with Takagi during class. He is not afraid to discipline his students, and on several occasions, has even thrown chalk at Nishikata's head in order to get him to pay attention. He is also known for confiscating chocolate from students during holidays such as Valentine's day and Christmas.
- He dislikes chocolate. In Chapter 45, he confiscates chocolates from his students whenever he sees and catches them exchange the sweets during Valentine's Day.
- In Chapter 134, he is engaged with his colleague, Tsukimoto-sensei, who is also Sanae's older sister.
|Main||Takagi • Nishikata|
|Supporting||Mano • Nakai • Sanae • Yukari • Mina • Takao • Kimura • Hamaguchi • Houjou • Tanabe-sensei|
|Minor||Sumire Takagawa • Tunnel Fisherman • Tunnel Fishergirl • Tunnel Misc • Principal • Mano's Friend • Class 4-2 Unnamed Girl|