A slider configured to reduce the wear of rotating bodies and an arc-shaped rail. The slider 32 includes: an insertion portion 321 inserted into the arc-shaped rail 31 through the slit 314; a first rotating body 342 which rolls on the outer peripheral wall 312, and a second rotating body 341 which rolls on the inner peripheral wall 311, wherein the second rotating body 341 includes a pair of lateral rotating bodies 411 disposed in both ends in the width direction and a central rotating body 412 disposed in the central portion in the width direction so as to be displaced in the sliding direction from the lateral rotating bodies 411 and wherein the lateral rotating bodies 411 and the central rotating body 412 are pivotally supported by a pivot member 51 provided so as to be swingable in the sliding direction in an insertion portion 321.