A power tool includes: a motor; a fan driven by the motor and defining an axis and a radial direction; and a housing for accommodating the motor and the fan therein, the housing including: a peripheral wall formed with a ventilation hole; and a grid partly covering the ventilation hole, the ventilation hole being positioned adjacent to the fan and having a shape defined by a circumferential surface, the grid including at least one elongated portion extending in a longitudinal direction perpendicular to the radial direction, and a distance from the axis of the fan to the circumferential surface is different from a distance from the axis of the fan to one elongated portion in the radial direction of the fan.