To provide a wheel bearing device with a rotation speed detector reduced in cost and improved in durability.

This wheel bearing device with a rotation speed detector is structured such that an inner ring 7 is pressed in a small-diameter step part 1b of a hub ring 1, and the inner ring 7 is axially fixed by a caulking part 1c, and is provided with a pulsar ring 11 externally fitted to the inner ring 7 and having magnetic characteristics alternately changing in the circumferential direction. In the wheel bearing device, a cover 10 is mounted to an end of an outside member 4; a sensor holder 20 with a rotation speed sensor 19 embedded therein is fixed at a position of its bottom part facing the pulsar ring 11; the pulsar ring 11 is composed of a support ring 12 formed into a cross-sectionally nearly-L-shaped form, and having a cylindrical part 12a pressed in the outer diameter of the inner ring 7 and an erected plate part 12b extending inward in the radial direction therefrom, and a magnetic encoder 13 integrally jointed to a side surface of the erected plate part 12b, and formed of a rubber magnet; and the inside diameter di of the magnetic encoder 13 is set larger than the outside diameter dk of the caulking part 1c.