To simply acquire a battery when battery rundown of a portable terminal device occurs in an outside location.

This secondary battery with a built-in control circuit of a portable information terminal is provided with: a current control part 201 for detecting a current of charge/discharge to control the current of charge/discharge; and a data processing part 202 for managing and storing identification information and use history information of the secondary battery, monitoring the current of charge/discharge detected by the current control part, transmitting control information of charge/discharge to the current control part, respectively evaluating battery capacity included in the use history and a battery remaining amount based on the number of times of charge/discharge and current integration of discharge, and causing another type of portable information terminal to display the identification information and use history information of the secondary battery when the other type of portable information terminal is allowed to use the secondary battery.

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