In a speed reduction motor comprising a motor and a speed reduction device connected to the motor for the purpose of reducing and transmitting rotation therethrough, a gear casing for housing gears of the speed reduction device is formed integrally with a rear gear bracket and a stator frame, so that the number of working steps are reduced and alignment of the gears is enhanced with high accuracy. Further, an opening portion is provided on an outer circumference of the gear casing through which the gears can be installed with ease of assembly.
