Provided are a ball joint and a manufacturing method therefor. The ball joint is manufactured by molding a holder (2) through casting by using a ball (10) as a core and joining a shaft member (11) to the ball (10) after the casting through electric resistance welding. The ball joint includes: the ball (10); a resin sliding contact member (3) including a first opening portion (31) and a second opening portion (32) that expose a spherical surface of the ball (10) in opposite directions; the holder (2) molded through the casting by using the ball (10) and the resin sliding contact member (3) as a core, the holder (2) being obtained by integrally molding a closing portion (23) that is held in contact with a part of the ball (10), which projects from the second opening portion (32) of the resin sliding contact member (3); and the shaft member (11) joined to another part of the ball (10) , which is exposed from the first opening portion (31) of the resin sliding contact member (3), through the electric resistance welding after the casting of the holder (2), to thereby construct a ball stud (1).