PURPOSE: To exactly inform by a sound agreeable to the ear that a set time has come, by generating plural alarm sounds so as to be overlapped, shifting in order their generation intervals whenever a constant interval of time passes after the set time has arrived.

CONSTITUTION: When an aiming circuit 14 becomes a set time, reset of an address counter 24 is released by an output of an alarm start signal outputting circuit 16, a data address of a natural sound stored in an ROM 22 is designated, a natural sound data is outputted, and a natural sound generating circuit 26 outputs a signal for informing the natural sound. This signal is sounded from an alarm device 46 through a mixer 44. After that, when a constant interval of time passes, reset of an address counter 34 is released, a melody sound signal is generated from the alarm device 46 together with a natural sound signal from the first alarming circuit 20. Also, after that, when a constant interval of time passes, reset of an address counter 40 is released, and from the alarm device 46, a natural sound, a melody sound and an electronic sound are generated so as to be overlapped.