A brushless motor includes a motor housing, a stator, a positioning projection, and a groove. The stator is fitted in the motor housing and includes an outer core and teeth, which extend in the radial direction of the stator. A radially outward end of each tooth is coupled with the outer core. Each tooth has a predetermined width in the circumferential direction of the stator. The positioning projection is located on the inner circumferential surface of the motor housing. The groove is located on the outer circumferential surface of the outer core. The groove is arranged on a radial line that passes through the center of the width direction of one of the teeth. The positioning projection is fitted in the groove to determine the position of the stator with respect to the motor housing in the circumferential direction.