Dinesh Yadav, a supporter of Anna Hazare who set himself on fire here last week, succumbed to his injuries early on Monday, police said.
"He died this (Monday) morning and his body has been given to his family. They have already left for Paliganj in Bihar to perform his last rites," a senior police officer told IANS.
There were media reports quoting his family that the 32-year-old had died last week, but police denied the reports.
Yadav shouted pro-Hazare slogans and poured petrol on himself and set himself on fire near Rajghat on August 23.
He sustained 70-80% burn injuries and was rushed to Lok Nayak Hospital.
The doctors at the hospital refused to comment on the case.