A brushless motor includes motor holder having a plate, a stator attached to the plate and a rotor having a rotary shaft. The rotary shaft has a lower end that protrudes from the stator. A sensor magnet is located near the lower end of the rotary shaft. The plate has a through hole through which the sensor magnet passes. This structure allows a unit including the stator, the rotor and the sensor magnet to be pre-assembled. The unit is then secured to the motor holder. This permits a set of standardized parts to be attached to a non-standard part in one step, which makes assembly more efficient.