PURPOSE: To allow a single key to function for a multiplicity of applications by using not only an operating key closing but also opening on each function detecting unit.

CONSTITUTION: When zero output is generated by opening a start/stop key SK, times on a time-keeper memory TM and a snooze memory SM coincide with each other, and if so, then an output is generated from a coincidence detecting means C, which actuates a buzzer driving control circuit BC to sounding. After a given period of time, the means BC stops sounding according to a signal from a driving stop signal generating means DS. Then, it operates for sounding intermittently at intervals of 5min according to an output 1 of the key SK, and a display tube 5 flickers. Next, when an N output of a counting detector CD and a zero detector ZD is generated while a down counter CD stops operating, and if the key SK is opened, conditions of AND circuit are satisfied and the counter CD starts counting. Sounding starts simultaneously with the count value coming to zero. Where the key SK is closed, FF is reset to stop sounding.