To provide a structure of a bearing device with a tone wheel capable of effectively protecting the tone wheel without requiring much higher machining accuracy or assembly accuracy.

The bearing device comprises a rolling element 4, inner and outer members 2 and 3 which are axially rotatable to each other via the rolling element 4, and an annular seal member 5 which is interposed between the inner and outer members 2 and 3 to perform sealing while maintaining the slidable contact with each other. The annular seal member 5 has a seal ring 51 to be attached to at least the rotation side member out of the inner and outer members 2 and 3. In addition, in this bearing device, the seal ring 51 comprises a cylindrical part 51a attached to the rotation side member and a flange part 51b continuous thereto. A tone wheel 7 is added to an outer end face of the flange part 51b, and a protective cover 9 to cover the outer side of the tone wheel 7 together with the end face of the rotation side member is fitted to the rotation side member.