A bearing device, provided in an inner ring thereof are a first cylindrical portion and a second cylindrical portion which is located in a vehicle inner side with respect to the first cylindrical portion and having a smaller outer diameter, wherein a pulser ring is fixed on the first cylindrical portion, a radial direction inner end side of a magnetic sensor is accommodated in a circumferential groove constituted by the first and second cylindrical portions, and a detecting element of the magnetic sensor faces the pulser ring in an axial direction.