A sheet punching device includes a punching unit, a cover member, an opening and closing sensor, a dust box, and a controller. The punching unit forms a punched hole in a sheet. The cover member can open and close the punching unit. The opening and closing sensor detects an open state of the cover member of the punching unit. The dust box is arranged in the punching unit and houses punch waste of the punched hole. The controller instructs continuation of a job of an image processing apparatus even if the opening of the cover member is detected by the opening and closing sensor without using the punching unit.