To easily manage the using situation of a charging device, and attending/leaving the company and whereabouts of staffs by connecting respective terminals with a sum terminal through existing PBX network.

A prepayment-dedicated card 1, a staff card 2, a card timer 3, a management personal computer 4 and the existing PBX network (existing extension) 5 connecting the card timer 3 and the management personal computer 4 are provided. The prepayment-dedicated card 1 having prepaid frequency data 1 or the staff card having prepaid frequency data and staff ID data can be used for the card timer 3. It is possible that the staff card which does not have prepaid frequency data can be used. The card timer 3 is connected to the management personal computer 4 via the existing PBX network 5 and attending/leaving the company and whereabouts data are collected/accumulated in the personal computer 4 from the card timer 2. Then, they can be displayed on a screen or printed out if need.