PURPOSE: To facilitate the registration of a schedule whose period is long by inputting a schedule number string and its frequency of repetition by using addition and subtraction.

CONSTITUTION: When data is inputted on Mondays and Thursdays of the starting ten weeks and only on Mondays of the following five weeks, (1001000)×10+ (1000000)×5 is inputted. A data input device reads a schedule character string and the input is repeated at a frequency when there is the frequency. One position in the number string is read and stored in a register of the data input device. It is discriminated whether an addition symbol is present or not after conversion and whether repetition is specified or not is judged when the addition symbol is present to repeat said operation. The registration of a schedule is performed easily even when days of data input are many or even when a test period is long.