Detective chief of Bidhannagar Police Commissionerate, Kankar Prasad Barui said Debjyoti Das was arrested after the class VI student's parents lodged a complaint with the police.
The victim used to stay at the school's hostel where he was allegedly beaten up by Das with a broken cricket bat on November 30 for being disobedient and not attentive to his studies.
The boy's head was broken and he received five stitches in a hospital, Barui said.
Barui said the parents complained to the police today and the the hostel superintendent was arrested.