To prevent the leakage of lubricants from the internal part of a bearing by providing a recessed groove in the peripheral surface of a locus side, forming a flange part extended toward a rotational side locus ring in one end side of a fixed side locus ring and forming a labyrinth seal between the flange part and the end surface of the rotational side locus ring.

A recessed groove 8 for suppressing the movement of a lubricant 7 to the upper end part of an inner ring 1 along a peripheral surface 12 is formed in the peripheral surface of the upper side in the peripheral surface of the locus 11 side of the inner ring 1. An inward flange part 22 extended to the inner ring 1 side is projectingly provided in the upper end part of an outer ring 2 and a labyrinth seal B is formed between the flange part 22 and the end surface 13 of the inner ring 1. Thus, the lubricant 7 moved through the outer peripheral surface of the inner ring 1 to its upper layer part is stopped by the recessed groove 8 and the transfer of a great deal of lubricant 7 to its upper end part is prevented. Also, the leakage of the lubricant 7 moved to the upper end side of a bearing A to the outside of the bearing A is prevented.