A 22-year-old man flung shoe at the ruling Nepal Communist Party chairperson, Pushpa Kamal Dahal "Prachanda", during a public function here on Sunday.
It was not immediately clear why the youth, who hailed from remote mountainous Jumla district, threw the shoe.
Prachanda, a former Nepal prime minister, narrowly escaped the shoe attack, party leaders said.
The incident took place when Prachanda was coming back to his seat after addressing the event, organised to mark the 1st death anniversary of communist leader Bharat Mohan Adhikari, they said.
The youth, a son of a former Maoist combatant, has been arrested and kept at Singh Durbar Police Circle, police said.