In-wheel motor fixing structure and in-wheel motor

The in-wheel motor fixing structure includes: an in-wheel motor (2) having a rotor (21) fixed to a wheel (1) of a vehicle S and rotating together with the wheel (1), a stator (22) provided inside the rotor (21) and rotating the rotor (21) by generating a magnetic force while being fixed to the vehicle S, and a shaft (25) fixed to the stator (22) on a rotating shaft of the rotor (21) in the stator (22); and a support member (3) of the vehicle S having a hole (31) into which the shaft (25) is inserted. A plurality of protrusions (251) formed in the circumferential direction of the shaft (25) are provided in at least a partial region in the longitudinal direction of the shaft (25), and a plurality of recesses (311) are formed in the inner circumferential surface of the hole (31), the plurality of protrusions (251) being inserted into the plurality of recesses (311), respectively. 轮内电动机固定结构包括：轮内电动机(2)，具有转子(21)、定子(22)和轴(25)，转子(21)固定到车辆S的车轮(1)，并与车轮(1)一起旋转，定子(22)设置在转子(21)内侧，并在固定到车辆(S)上的同时通过产生磁力使转子(21)旋转，轴(25)在转子(21)