The dead man was identified as 52-year-old Kamara Chadara.
The six persons were injured in the blast in Dasera village of Jajarkot district on Thursday.
A man found the bomb in a forest and brought it to a workshop so that he could extract the iron parts. It exploded when he tried to take it apart.
Police suspect the bomb might have been concealed in the forest during the decade-long Maoist insurgency that ended in 2006.