The accused, identified as Ramnaresh Nishad, was arrested when he was trying to commit suicide, they said.
During interrogation, Nishad, who confessed to the crime, said he killed his son after he got furious at his wife for stopping him to have more liquor, a police official said
The incident took place in Khaptiha village on December 24. The boy died on the spot.
The accused was absconding after the crime.