To provide a power tool wherein the operation of a brushless motor is stabilized by effectively cooling a switching element of a circuit board.

An impact driver (the power tool) 50 comprises: a cylindrical motor housing part 50a for storing the brushless motor 3; and a power transmitting housing part 50b, and the brushless motor 3 is constituted of: a cylindrical stator 12; a rotor 13 arranged inside the stator 12 concentrically therewith; the circuit board 22 having the switching element 21 for controlling the rotation of the rotor 13; and a cooling fan 15 for introducing cooling air from an air inlet 17 of the motor housing part 50a into the motor housing part 50a to cool the circuit board 22 and the stator 12. Near the air inlet 17 in the inner wall of the motor housing part 50a, an air flow control rib 50g is provided extending from the inner wall for the motor housing part 50a inward in the radial direction.

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