|Japanese Name:||笹原 幸治郎|
|Romanized Name:||Sasahara Kōjirō|
|English Name:||Koujirou Sasahara|
|First Appearance:||"Nichijou Episode 1"|
|Japanese VA:||Yoshihisa Kawahara|
Koujirou Sasahara is a flamboyant high school boy who likes to think he is an aristocrat, when in reality his family are just farmers. He likes to ride his goat to school and is often seen with his butler. Misato Tachibana has a crush on him but shoots him with various heavy weapons to hide it when she feels embarrassed about it.
Koujirou wears glasses, and a black outfit with a white jabot (actually made of tissues). He doesn't actually need to wear glasses and only wears his for show, as shown in one episode where Misato Tachibana was guiding him.
Koujirou behaves much like an aristocrat. He is almost always seen calm and collected, and very rarely, if ever, gets visibly angry. He can be rude to others at times, but he can also be kind and gentlemanly, such as when he handed a piece of his collar to Misato Tachibana to wrap around her hand when she accidentally smashed his glasses. When Misato remarked that he should be mad at her for breaking his glasses, he responded that glasses do not feel pain, but cutting your hand hurts. Adding to his aristocratic air is his insistence that he ought to ride a goat to school, to avoid walking.
He always refers to Misato by her full name. He doesn't seem to care that Misato often shoots him with various weapons, and always appears unfazed no matter how many times he is shot. He hasn't been shown to be aware that she has a crush on him either.
It is revealed in Episode 2 that he is the president of the Drama Club.
Mio has a crush on Koujirou. While he very rarely interacts with her, and doesn't seem to think about her much, she gets very nervous around him.
Misato also has a crush on Koujirou but has a very tsundere attitude towards him. It is said that they are childhood friends. Misato is frustrated that he doesn't work hard enough at kendo.
|Trio Sucharaka||Mio Naganohara · Yuuko Aioi · Mai Minakami|
|Shinonome Laboratory||Hakase (Shinonome) · Nano Shinonome · Sakamoto|
|Faculty||Principal Shinonome · Kousuke Oura · Izumi Sakurai · Manabu Takasaki · Kana Nakamura|
|Class 1-O||Yuria Sekiguchi · Makoto Sakurai|
|Class 1-Q||Mio Naganohara · Yuuko Aioi · Mai Minakami · Nano Shinonome · Haruna Annaka · Tanaka · Tsuyoshi Nakanojou|
|Class 2-P||Kenzaburou Daiku · Koujirou Sasahara · Misato Tachibana · Weboshii · Fe-chan|
|Others (females)||Yoshino Naganohara · Mihoshi Tachibana · Tamamura · Princess Starla · Yuuko's Mother · Double Cheeseburgirl · Sumika · Tanabo · Ogo · Kimiko|
|Others (males)||Hajime Sakurai · Mi-chan · Dolph · Nakanojou's Father|
|Others (animals)||Buddy · Karasu · Oguri Cap|