The incident occurred at Ghorma village when a bus full of pilgrims were on the way to Basukinath temple in Dumka district to offer puja after visiting Babadham temple in Deoghar district, the police said.
The victims were sitting on the roof of the bus when they came in contact with a live electric wire, sources said.
The victims were residents of Pakadia village in Maharajgunj of Uttar Pradesh.
While 45-year-old Mithilesh Yadav died on the spot, Sadhu Yadav fell down from the roof and suffered serious injuries, sources said.
Sadhu Yadav was rushed to Sadar Hospital in Dumka.