A device that controls charging and discharging of a lithium ion battery (3) that starts an engine starter (1), includes: a voltage sensor (S1) that detects the voltage of the lithium ion battery; a current sensor (S2) that detects the current of the lithium ion battery; and a control section (30) that controls charging and discharging of the lithium ion battery. The control section (30) calculates capacity degradation rates of a cathode and anode of the lithium ion battery based on detected values of the voltage sensor and the current sensor at the time when a first time has elapsed, and at the time when a second time longer than the first time has elapsed, from startup of the engine starter, and limits the charging and discharging of the lithium ion battery based on comparison results between the capacity degradation rates and determination criterion values.