The ultra, identified as Teli Kadraka, was killed in the gunbattle with jawans of Special Operation Group (SOG) and police in Badamatura forest of Bandhugaon area, Sub-Divisional Police Officer (SDPO) Y J Rao said.
The body of the rebel, an area commander of Jhanjabati Area Organising Committee of Maoists, has been recovered, he said adding that a gun, some ammunition and naxal materials were seized from the spot.
The encounter took place when some ultras present in the forest were spotted by the security personnel during a combing operation, police said.
Other members of the naxal group, however, managed to escape, they said.
Steps have been taken to intensity combing operation and patrolling in the entire area after the exchange of fire, they added.