PURPOSE: To obtain an easy-to-use copying machine by providing a mode switching means which switches on every operation, a means which displays corresponding data during the operation of the switching means, a detecting means for an operation time, and a copy mode switching inhibiting means which inhibits copy mode switching operation after a specific time is elapsed.

CONSTITUTION: A CPU is reset and initialized with keys 80W103, its internal timer is set, and a mode changeover key 106 is operated. The on edge of the key is detected and a binding margin is displayed 77, so that the timer measures the key depression time in binding mode (where an LED 106a is on). The copying machine when in normal mode (where the LED is off) enters the binding mode. When the on edge is not detected, the quantity of copies is displayed according to whether the off edge is detected or not, and the counting state of the timer is decided to perform copying operation. The when the key 106 is pressed continuously exceeding the time-up period of the timer, the length of the binding margin is displayed on a device 72 and it is decided that key operation for binding margin confirmation is performed, so that the modes are not changed even after the operation of the key 106 is finished. Consequently, the device becomes easy to use practically.