A paper punch includes a plurality of punch seats movably disposed along a slide board mounted on a base, a press board pivotably connected to the base to press punch heads of the punch seats, and a plurality of control members respectively disposed on the punch seats and operable to releasably lock the punch seats on the base. Each punch seat has a force transmitting member movably disposed on a die holder to transmit a pressing force of the press board so as to press the punch head downwardly to perform a firm and stable punching operation.