PURPOSE: To prevent a faucet fitting part from damage due to thermal expansion, by forming the faucet fitting part from an intermediate bracket of small thermall expansion coefficient and a pump casing of large thermal expansion coefficient and forming hollwed parts in the periphery of the faucet part of the pump casing.

CONSTITUTION: Operation of an electric motor 1 rotates a motor shaft 1A, magnet holder 2 and driving permanent magnet 5, then a driven permanent magnet 7C and impeller 7B are rotated. An intermediate bracket 6 and pump casing 7A, forming a faucet fitting part, are thermally expanded by hot water, passing in a pump 7, here the thermal expansion coefficient of the pump casing 7A is larger than that of the intermediate bracket 6, though mutual contact pressure in the faucet fitting part tends to increase, an abnormal rise of stress in the faucet fitting part, followed by damage of the fitting part, can be prevented by forming hollowed places 7Aa in the periphery of the faucet part of the pump casing 7A.