The incident took place when the girl was going towards the Shikaripara block office with her friend and three others joined them mid-way, Deputy Superintendent of Police A K Srivastav said.
The four took the victim, a class VIII drop out, to a vacant quarter near the block office and gang-raped her, they said.
Hearing the girl's cries for help, the locals rushed to the spot and caught hold of two of the accused, aged 13 and 15 respectively, he said.