A housing (20) comprises an opening (alpha) that opens in one direction. During assembly, the opening (alpha) of the housing (20) faces upwards. From above, a web washer (38), an electric motor (21),and a motor fixing screw are attached, a first intermediate shaft (31) and a second intermediate shaft are press-fitted, and a lower bearing, an output shaft (23), a second intermediate gear, and a first intermediate gear (27) are attached. Next, a cover (24) is mounted to the housing (20) from above. Next, an actuator lever (13) is coupled to the tip of the output shaft (23) from above. Yield canthereby be increased because the electric actuator (11) can be assembled without inverting the housing (20).