To provide a sign in/out data management system and the like facilitating confirmation and summation of the sign in/out data about an employee by an employer and allowing the employee to check own sigh-in/out condition with ease.

This sign in/out data management system is provided with a time recorder, which has a controlling means, a clock means, a display means, a card recognizing means, a printing means, a storage means and a communication means, and a communication means for connecting to the time recorder. By means of the time recorder, sigh in/out information of the employee is printed on a predetermined recording card while this information is stored as the sight in/out data in the storage means, and the sign in/out data stored in the storage means are summed and managed by the management computer.