PURPOSE: To simplify integrated circuit design by providing a watch driving system and an additional function circuit on individual chips.

CONSTITUTION: When mechanical alarm set circuit 28 reaches a set time, output line 40 becomes H, and the output of circuit 28 is applied to one input of AND gate 34. At this time, since modulation frequency 42 of frequency divider circuit 18 is applied to the other input of AND gate 34 previously, the frequency division signal is applied to alarm pre-driver 36 and driver 38 and is amplified and is sent to alarm tone generation nuit 30, thus reporting the alarm tone. Then, modulation frequency 42 from frequency divider circuit 18 can be changed without change of additional function circuit 32 of another chip.