A laser scanning motor includes a coreless flat brushless motor disposed in a rotatable polygonal mirror having polygonal outer mirror surfaces. A light beam applied to the polygonal mirror is deflected by controlling the rotation of the coreless flat brushless motor. Poles and a bearing holder of the coreless flat brushless motor in a rotor assembly are formed of a plastic magnetic material. When manufacturing the laser scanning motor, the poles and the bearing holder are formed simultaneously by filling the plastic magnetic material in one operation, and then firmly securing the poles and bearing holder to the rotor assembly.