A built-up stepping motor (M) includes upper and lower housings (11, 12) each having an internal space and joined together with a support plate (18) disposed therebe­tween. The lower housing retains therein a stator (A, B) and a rotor (19) disposed in the stator, while the upper housing holds therein a reduction gear (20) for reducing the output speed of the motor. The output end of a rotor shaft (19b) extends through the support plate and meshes with a first gear (22) of the reduction gear. The upper and lower housings are assembled together by interlocking engagement between locking projections (12f) and mating holes (11f). A shock-absorbing damper (24) is disposed between two stator cores (A, B) to protect them against chattering.