Sanjeev Kumar, who was carrying the pistol in his bag, tried to escape when it was detected by Central Industrial Security Force (CISF) personnel during a security scan last night.
Kumar claimed that the firearm was "placed" in his bag, Assistant Commandant CISF Abhijeet Singh said, adding that he was handed over to the Indira Puram police.
The accountant was sent to 14 days judicial custody after he was produced before a magistrate today.