Asu Giri, a resident of Khedapa village near here, was facing trial in a case booked under POCSO Act and was in the prison since November 8, 2015, Central Jail Superintendent, Vikram Singh said.
The inmate today slipped into a narrow passage behind the jail store room and hanged himself from a hook stuck in a wall, he said.
Other inmates saw him hanging this afternoon and informed the jail administration. The doctors from the dispensary who declared him dead, he said.
"For the past some time he was appearing quite disturbed and would be seen silent most of the time both in and out of the barrack," Singh said.
Police have sent the body for postmortem and an investigation is on.
Before this, two jail inmates, who were serving life imprisonment here, had also allegedly committed suicide in the similar manner in last few months.