To provide a bearing sealing device that can improve its creeping resistance and sealing performance at the same time by enhancing the force of fitting (pressing) a slinger into a bearing ring.

A slinger 20 (a slinger base part 20b) has a thinner part 20c thinner than the other part and formed along the peripheral direction. The bearing ring has a stepped part 28 on which the thinner part of the slinger abuts and which is formed continuously along the peripheral direction. The stepped part has a tapered face 28s formed in a concentrically circular shape with respect to the rotational axis of a bearing while assuming a tapered conical gradient along the direction of tending from the outside of the bearing toward the inside of the bearing. When the bearing ring is fitted into the slinger, the thinner part abuts on the stepped part and it is elastically deformed along the tapered face. Thus, the slinger is positioned and fixed to the other bearing ring.