Ram Swarath Yadav (45) died in his house at Barhi village after the bomb went off in the morning, Jainagar Station House Officer (SHO) Roshan Kumar said.
Four of his family members were injured.
The SHO said it was suspected that the bomb, which was either made in the house or brought from outside, was kept in the house by the deceased himself who had criminal cases pending against him.