The potato chips concerned have the brand name “R 18+ Curry Chips”, media outlets including Asahi Shimbun and Fuji TV said.
According to the manufacturer’s website, under-18s are “banned” from eating the potato chips, which are “so spicy that they might cause you pain”.
A hefty amount of extremely hot pepper known as “ghost pepper” is used as an ingredient, the firm says on its website.
Those with high blood pressure and weak stomachs “are absolutely prohibited” from taking bites and those who are “timid and have no guts” are also discouraged, the website warns.
Tokyo emergency services, the school and the chip maker were not immediately available for comment when contacted by AFP.