A sheet hole-punching device includes a punch member having a leading end with a hole-punching blade, a base frame for movably supporting the punch member in a hole-punching direction, a drive motor for driving the punch member, and a transmission device for transmitting rotational force of the drive motor to the punch member so as to rotate the punch member. The transmission device is disposed between the drive motor and the punch member. A cam device is disposed between the base frame and punch member, and converts a rotational movement of the punch member into a hole-punching direction movement so as to move the punch member in the hole-punching direction while rotating the punch member.