Jitendra Gautam started showing blue film to the children on his mobile phone when the principal of Takshasila Public School had gone out for an urgent work.
Residents of the area badly assaulted him and handed him over to police.
On receiving information about the incident, the principal of the school rushed back and filed a complaint.
"He has been arrested and a case has been registered against him on the complaint of Urmila Sharma, the principal of the school," DySP Anil Yadav said.