Dipankar Mal had returned to the hostel yesterday with some food from home which five other boys stole and ate. When he protested they locked him inside a room and tortured him.
The boy's lodged an FIR with the police yesterday itself and the five boys, all of them his seniors, were arrested, the police said.
Dipankar was admitted to Salbani Health Centre and gave his statement to the police.
"They cut me with blades and then beat me with sticks in the room," the police quoted him as saying.
The five boys were later rusticated, the school authorities said.