A carpet stretcher device has an engaging head adapted to engage carpet and having a rear end, a housing connected with the rear end of the engaging head, an electromagnetic coil arranged in the housing and adapted to generate an electromagnetic field, a plunger movable in the housing in a longitudinal direction under the action of the electromagnetic field of the electromagnetic coil and adapted to strike the housing so as to transmit its strike to the rear end of the engaging head. The electromagnetic coil has a throughgoing passage extending in the longitudinal direction. The plunger has a central portion extending through and guided in the passage of the electromagnetic coil and two end portions connected with two opposite ends of the central portion and located outwardly beyond two opposite ends of the coil.