The Buddhist monk had put lighted rags on a stick into the nest in the temple, but dropped it and ran when the hornets flew out and attacked him, Niigata prefectural (state) police official Yuichi Ozaka said. The fire occurred Wednesday.
He said the monk, Atsushi Sato, 41, suffered burns on his ears, face and left hand, but he was not stung.
The temple in Ojiya City, northern Japan, was burned to the ground, along with the nest, Ozaka said.
Police said Sato's burns were not life-threatening.