Police said the incident took place when the boy, studying in Class I, went near the phone while its battery was being recharged and blew at it.
The phone exploded and the flames charred a part of his body.
Hearing his cries, the family members rushed to the room and doused the flame with water, police said.
The boy was rushed to the sadar hospital here and was declared brought dead by its authorities, police said, adding, the phone was found to be a China-made product.