PURPOSE: To exactly set data by a single switch by masking a strobing signal during the operation of a data setting switch, and fetching the set data by the first strobing signal after the restoration of the switch.

CONSTITUTION: When a data setting switch 12 is operated, a switch operating period detecting part 15 detects it, transmits a clock signal 13 to a data generating part 16, and counts a counter. As the result, the data outputted from the data generating part 16 are changed, and displayed on a data display part 17. A second clock signal 14 inputted to a strobing signal generating part 18 is masked in the operating period of the data setting switch 12, and the strobing signal is not supplied to a set data outputting part 19. Then, when the data setting switch 12 is restored, the strobing signal generating part 18 supplies the strobing signal again, and the set data outputting part 19 fetches the set data outputted from the data generating part 16 by the first strobing signal after the restoration of the data setting switch, and outputs the set data.