The militant, identified as Partha Gogoi alias Ramen Barua, surrendered before Dibrugarh Superintendent of Police Arabinda Kalita and senior army officers.
The militant also deposited an AK-56 rifle, a magazine and ten rounds of ammunitions.
Kalita welcomed Gogoi, who was trained in Myanmar, back to the mainstream and hoped many more misguided youths would follow his path.
Gogoi said he decided to surrender due to health reasons and the fact that he realised the futility of armed struggle.