PURPOSE: To develop the max. punching capacity by small force by a method wherein a punching member is moved slowly through an eccentric cam when load is high but moved rapidly when load is low.

CONSTITUTION: Sheet materials 2 are punched by a punching means 3 and fed to the binding position of a binding member 6 by a feed means to be bound by the binding member 6 of a binding means 7. At this time, the punching member 17 of the punching means 3 is moved slowly by the profile of an eccentric cam 93 when high load is applied to the motor 90 driving the eccentric cam 93 but moved rapidly when low load is applied to said motor. By this constitution, the work load required at the time of punching is dispersed and punching capacity is developed to the max. degree by small force and the output of the motor 90 can be smoothly utilized to the max. degree.