To provide a ball joint having high reliability and reduced weight.

This ball joint 10 is provided with a ball stud 100, having a columnar stud part 110 and a ball part 120, having a spherical side face and the center positioned on an axis of the stud part 110; a resin ball seat 210, having a recessed part 212 having a spherical face and fitted into the ball part 120 to freely and relatively rotate and freely slide; a resin housing 220 storing the ball seat 210; and a resin support bar 230 which is molded integrally with the housing 220. The support bar 230 has a bar part 231, constituting a central part along its axis.