To easily attain management related with the period of carry or the number of times of carry of a portable device by measuring the number of times of carriage and/or the period of carry while a power is supplied from a battery.

When a voice guide device is detached from an outside charger, the switch of a switch circuit part 16 is closed, and a power is supplied from a battery 11 to a storage part 12 and a control arithmetic part 13. The control arithmetic part 13 starts a carry management, and adds 1 to the number of times of carry data stored in the storage part 12. Then, the measurement of the carry period is started, and 1 is added to the period data and the total period data by each second, and an update processing is operated. When the voice guide device is returned, the voice guide device is placed on the charger. Then, when the switch of the switch circuit part 16 is opened, and power supply to the control arithmetic part 13 is disconnected, the control arithmetic part 13 stops the carry management.