Ventsislav Kozarev, 47, who set himself on fire with petrol in the southern town of Smolyan on Wednesday, succumbed to his injuries in the afternoon, the hospital treating him said. He was said to be distraught after recently divorcing his wife.
Bulgaria has seen a spate of similar incidents in recent weeks in a wave of angry and sometimes violent protests against poverty and corruption that in late February prompted prime minister Boyko Borisov to resign.
The small Balkan country will hold snap elections on May 12 with Borisov's GERB party tipped to win the vote but fall short of a governing majority.