Aam Aadmi Party (AAP) chief Arvind Kejriwal was attacked on Friday during his roadshow in south Delhi's Dakshinpuri area.
According to reports, the assailant slapped and punched Kejriwal while he was campaigning with party supporters.
The man has been handed over to the police by AAP volunteers.
This is not the first time Kejriwal has been attacked.
On March 28, the former Delhi chief minister was reportedly attacked by a man, who claimed to be a supporter of anti-corruption crusader Anna Hazare, during his election rally in Haryana.