The incident happened in Patna yesterday night, the police said.
The jawan, identified as Pujan Guru, accidentally shot himself with his service rifle while he was on duty outside the chief minister's official residence at 1, Anney Marg, between 11 pm and 12 midnight, City Superintendent of Police, Central, D Amarkesh said.
The bullet hit his chest, the police officer said.
The jawan was admitted to the ICU of Patna Medical College and Hospital (PMCH), the city SP said, adding, that the rifle has been seized.