To provide a cross roller bearing which can be easily assembled and can suppressing skewing of rolling elements.

A cross roller bearing in which an inner member and an outer member rotate comprises an inner-side V groove provided in an annular shape along an outer circumferential surface of the inner member to have an opened V shape toward the outer member side, and an outer-side V groove which is provided in the annular shape along an inner circumferential surface of the outer member to oppose the inner V groove and have the opened V shape toward the inner member side. A plurality of rolling elements rolling in contact with the inner-side V groove and the outer-side V groove and having a cylindrical shape are interposed, and the rolling axes of the rolling elements adjacent to each other from among the plurality of rolling elements are made orthogonal to each other. Between the rolling elements adjacent to each other, a retainer is interposed which comprises a planar part whose central part projects at a part facing the rolling element to be capable of coming into contact with the rolling element, and an inclined part whose amount of projection decreases from the planar part to an end.