Adel Kedhri (27) set himself on fire in the centre of Tunis on Tuesday and died in hospital on Wednesday.
"This young man is already dead", a medical source in Mourouj Hospital told Reuters.
The act recalled the self-immolation of Mohamed Bouazizi, whose death in December 2010 led to a revolt in Tunisia that spread across the Arab world.
The economic and social problems that fuelled Tunisia's uprising have yet to be solved in a country now deeply polarised and still awaiting a new constitution to advance a transition from autocracy.
Kedhri's death occurred while Prime Minister-designate Ali Larayedh sought a confidence vote for his new Islamist-led government from the National Constituent Assembly.
"This incident shows the desperation," parliamentary speaker Mustapha Ben Jaafar said during an assembly session.
Unemployment fuels despair
Kedhri set himself ablaze outside the municipal theatre in the capital's Habib Bourguiba Avenue, the focus for protests that toppled former president Zine al-Abidine Ben Ali two years ago.
Several Tunisians have immolated themselves in the past two years in protests emulating that of Bouazizi, a street vendor who torched himself in the town of Sidi Bouzid after a police officer confiscated his fruit cart.
Bouazizi's death led to protests that ended with Ben Ali's overthrow and inspired rebellions elsewhere in the Middle East
Ali Larayedh said on Tuesday that unemployment, rising prices and providing security for all Tunisians will be the new government's priorities.
Tunisia's unemployment rate stands at about 17%, with graduates forming a large proportion of the jobless total.
The last government, led by Hamadi Jebali, collapsed after the premier's own moderate Islamist Ennahda party rejected his plan for a technocrat cabinet to lead Tunisia to elections.
Jebali had proposed this as a way to calm unrest over the assassination on February 6 of secular opposition leader Chokri Belaid by what the authorities say was a group of Salafi Islamist militants, four of whom have been arrested.
Larayedh, who was interior minister under Jebali, has named independents to take several portfolios but failed to bring additional secular parties into the Ennahda-led coalition.
The political crisis has delayed talks with the International Monetary Fund on a $1.78-billion loan. – Retuers