PURPOSE: To provide a ΔT control system charging control circuit, in which the effect of an ambient temperature is eliminated and full charge is decided accurately.

CONSTITUTION: The temperature of a battery 7 during charging is detected by a temperature detecting means such as a temperature sensor 6 and full charge control is conducted when the rate of the temperature change of the battery 7 obtained from a detecting temperature reaches a preset threshold or more in a charging control circuit. A storage means such as a memory 4, in which a plurality of thresholds corresponding to the temperature of the battery 7 are stored, and a threshold changeover means such as a control section 5 changing over a temperature to the threshold corresponding in response to the temperature detected by the temperature detecting means are provided.