PURPOSE: To display time data in accordance with user's designation by storing information, which indicates whether time data should be always displayed or not, into a memory and taking in time data from a clock circuit in accordance with stored contents to display it on a display part.

CONSTITUTION: When the clock display mode is set by key input at the time of operation, it is stored and held in a memory 13 by a mode designating part 11. A display control part 14 reads out this clock display mode from the memory 13 to discriminate whether time data should be always displayed or not. When it should be always displayed, the display control part 14 reads out present date, day of a week, time, etc., from a clock managing part 15 and collectively display them on a display part 17 and is returned to the original normal key input state.