To reduce weight, and to facilitate standardization of automobile assembling in a wheel bearing device for transmitting electric motive power to a wheel.

In this wheel bearing for transmitting the motive power from a motor 1 to the wheel, the wheel bearing uses an outer member 41 for integally forming a flange 44 on the outer periphery. An inner member 42 is rotatably driven by the motor 1 via a shaft 60 fitted to the inner diameter hole 49. The inner-outer members 41 and 42 have rollingly traveling surfaces of double rows, and a rolling body 43 is interposed between both members 41 and 42. The inner member 42 has an installing flange 45 of the wheel 52.