PURPOSE: To check the fitting state of the counter optionally and to prevent illegal use by detecting whether or not there is a stepping coil by a magnetic detecting element before the counter counts up.

CONSTITUTION: A counter controller 1 consists of the stepping coil 3 connected to both ends of a diode 2 and the magnetic detecting element 4 provided nearby the stepping coil 3. Here, the time t1 from power-on operation for exciting the stepping coil 3 to the excitation of the exciting counter and the time t2 from the power-on operation to the operation of the magnetic detecting element 4 are so set t2t2 and the output of the magnetic detecting element 4 is checked at the power-on time and at optional time T when t1>T>t2. Therefore, whether or not there is the stepping coil 3 is detected by the magnetic detecting element 4 before the counter counts up. Consequently, whether or not the exciting counter is fitted can be monitored at an optional point of time and illegal use can be monitored.