A device for detecting a battery within a charger includes a battery detector and a regulation voltage controller that limits a battery charging terminal voltage to a battery regulation voltage. The battery detector generates a battery existence signal if a battery charging terminal voltage is not greater than a battery detection reference voltage at an end of a predetermined time period. The battery charging terminal voltage is limited to a normal mode value of the battery regulation voltage if the battery existence signal is generated. The battery detector also detects for removal of the battery after the battery regulation voltage is set to the normal mode value during charging.