The external device information acquirer (142) acquires charge identification information from an electric energy supply source and discharge identification information from an electric energy supply destination. The electric energy quantity acquirer (144) acquires the electric energy quantity supplied from the electric energy supply source to the secondary battery. The charging state DB (161) stores the charge identification information of the electric energy supply source in association with the electric energy quantity acquired by the electric energy quantity acquirer (144). The charge/discharge setting DB (162) stores discharge permission information representing an electric energy supply source and an electric energy supply destination to which the electric energy stored in the secondary battery from the electric energy supply source is dischargeable. The discharge permission determiner (145) determines whether the electric energy supplied from the electric energy supply source identified by the charge identification information stored in the charging state DB (161) is dischargeable to the electric energy supply destination identified by the discharge identification information based on discharge permission information.
