PURPOSE: To prevent foreign substances from entering into a bearing and to reduce the axial length thereof by packing grease in the bearing in the way that the internal peripheral part of a primary ring whose external peripheral part thereof is mounted on an external ring is embraced with the external peripheral part of a secondary ring whose internal peripheral part with the internal face of the recess part having a shape approximately the same as the afore-said internal peripheral part is mounted on an inner ring.

CONSTITUTION: A stationary ring 27 is formed by covering a ring-like core metal 32 consisting of both a disk part 30 and a bent part 31 with rubber and the external peripheral part 35 of the ring 27 is engaged and fixed in the ring-like recess 36 of an external ring 21. On the other hand, a turning ring 28 having an annular recess 37 is made of synthetic resin and the internal peripheral part 38 is engaged and fixed in the annular groove 41 of an internal rig 22. The internal face 43 of the recess part 37 and the internal peripheral part 42 of the core metal 32 of the stationary ring 27 have approximately the same rectangular sectional outline so that the internal peripheral part 42 is in close contact with the internal face 43 and is covered with the recess part 37 in the internal radial direction of said part 42. Consequently, a bearing has sufficient grease sealing performance to prevent foreign substance from entering, and can reduce the size in an axial direction and the fabricating/ assembling cost of the bearing.