To provide a power tool improving the water resistance and a dust-proof property of a motor portion and a control circuit portion.

The power tool includes a stator 6a having winding wire, a motor 6 having a rotor 6c capable of rotating in the stator 6a, housings (2, 4) storing the motor 6, and tip end tool holding portions (3, 7) projecting out from the housings and driven by the motor 6. A water-proof case 20 covering the stator 6c, a driving circuit 15, and a switch 16 is provided in the housing. A brushless DC motor using a permanent magnet for the rotor 6c is used as the motor 6, and the water-proof case 20 is constituted by metal of a non-magnetic element or polymer resins. On an outer peripheral surface of the water-proof case 20, a plurality of heat radiation fins 25 for heat radiation is provided.

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