To provide a design of a reduction transmission structure capable of generating a higher torque.

The external rotation drive structure comprises an external rotation structure, a structure 2 being installed while inclining, a drive motor 3 and a transmission gear 4 wherein the external rotation structure has an axle hub structure 11. When one fixed shaft 12 is provided in the center and the axle hub 11 is rotated, the structure 2 being installed while inclining provided on the fixed shaft 12 can be selected. The structure 2 being installed while inclining is provided with one or more fixed shafts and a drive motor exhibiting an inclining state, and a prime move gear or a friction wheel constituting the transmission gear is provided at the end of its output shaft. A function for driving the external rotation drive structure by the drive motor 3 is achieved by providing the axle hub 11 with a passive inner ring gear 42 or an inner ring friction wheel. Drive torque and transmission power can be increased by providing one or more motors.