PURPOSE: To put an external device in operation by a latch means and a stop means by providing the latch means which turns on when successive pulses of a timer alarm are inputted.

CONSTITUTION: When an alarm signal is outputted from BD, the output of a one-shot circuit 17 is passed through an FF to output 8. Alarm signals 7 and 8 are ANDed to obtain an output 9. Further, if a time-casting signal is outputted from the BD, an output 9 is obtained. Namely, the alarm signal and other signal pulses are detected and selected on the basis of signal width by using a pulse width detecting means and it is decided that only the alarm signal pulse width is an on input. When a signal is inputted to 9, the output 10 of the latch means 4 turns on and a transistor as a switch means turns on, so that the operation of the external device is started. Thus, the external device is turned on and off by utilizing a timepiece with an alarm.