To display a bar code on a display part of a cellular phone and to manage a work time of an employee by data read in a bar code reading procedure.

As a method wherein each employee reports attendance start/end times to store them in electronic data, employee identification information is displayed on a display part of a cellular phone by a bar code to read it by a bar code reading means, and the times are recorded in a storage procedure located in the bar code reading procedure as the attendance start time and the attendance end time.