Kulwindar Singh, who was from Punjab, was on duty at gate number two in the military area last night where he shoot himself, SHO Sadar Sanjay Bothra said.
The body has been taken to PBM government hospital for postmortem.
The exact reason behind the suicide is not clear, the SHO said.
Defence spokesperson S D Goswami said that a Court of Inquiry has been ordered to ascertain facts of the incident.