PURPOSE: To eliminate useless electric power consumption in a motor-drive pump, which is used to supply kerosense, etc., to a cartridge tank, by controlling the operation of a motor, via a liquid level detecting switch containing a temperature-sensing deformable metal, taking advantage of a difference in amperage between no-load operation time and load operation time.

CONSTITUTION: When the kerosene in a kerosene tank is poured is poured into a cartridge tank, by pushing a manual switch SW1, an electric current flows from an electric power supply E to a motor M, and the kerosene is sucked up owing to an operation of a pump and poured into the tank T. At this time, since the temperature sensing part 11E of a liquid level detecting switch 11, which is inserted into the tank T together with a guide 3, is thin and has small heat capacity, its temperature rises in a short time and the sensing part 11E deforms into a memorized shape in order to drive a movable contact plate 11F. Thus, a movable contact 11G is brought into contact with a fixed contact 11H, so that the electrifying circuit is self-held. Meanwhile, when the liquid level in the tank T goes up, and approaches the temperature sensing part 11E, the temperature sensing part 11E is cooled. Then, the movable contact plate 11F returns to its original state, and the movable contact 11G separates from the fixed contact 11H, thereby stopping the motor M.