PURPOSE: To prevent mistake and omission in the report of working time to improve the accuracy of added data by providing a means to add up all working time recorded in a recording media and the data of working time to be newly recorded and displaying the result on a display means.

CONSTITUTION: The working time of all the work concerned is added up. A control section 1 judges whether or not the added time is 24 hours or less. That is, the sum total of working time of the day can not exceed 24 hours, i.e., a day, therefore, in the case of exceeding, it is judged that working time was exaggeratively reported, and the 'error' is displayed on a display section 6 as wrong working time. In the next step, when working data are newly input or modified, working time is added up again, and it is judged whether sum total is normal or not. If it is normal, the sum total is displayed. Such procedure is conducted for every recording and modifying. To finish inputting, an IC card 7 shall be discharged after writing input data on the file of the IC card.