The leopard caught Sunil (8) by his head and started to drag him when his father Gul Singh (32) came to the rescue of his son.
The leopard attacked Singh before disappearing from the spot, Nalchha police station sub-inspector O P Verma said.
He said the leopard tore off an ear of Sunil and inflicted injuries to Singh below his abdomen.
Area Divisional Forest Officer (DFO) Gaurav Choudhary said that the pug mark of the leopard had been captured and they were searching for the animal.