To provide a ribbon cage of a bearing of which the manufacturing cost can be reduced by minimizing the number of members constituting the cage, and simplifying shapes of the members.

One of retaining members 10, 20 which are configured in such a manner that curved retaining parts 11, 21 retaining a rolling element 30 and flat coupling parts 12, 22 are alternately formed in annular shapes has a penetration hole 13 protrusively formed at a coupling part 12, and the other of the pair of retaining members 10, 20 has a cylindrically-projected coupling projection 23 which is inserted into the through-hole 13 of one retaining member 10 at the coupling part 22. By diametrically enlarging and caulking a tip side of the coupling projection 23 inserted in the through-hole 13, the pair of retaining members 10, 20 are coupled with and fixed to each other.