A spherical annular seal member 40 includes: a spherical annular base member 38 which is defined by a cylindrical inner surface 34 defining a through hole 33 in a central portion, a partially convex spherical surface 35, and annular end faces 36 and 37 on large- and small-diameter sides of the partially convex spherical surface 35; and an outer layer 39 formed integrally on the partially convex spherical surface 35 of the spherical annular base member 38.