Ball joint and ball joint manufacturing method

The present ball joint 10 is provided with a ball stud 21 having a spherical ball section 23 and a shaft-shaped axis section 25, and a holder 51 for holding the ball section 23 so as to rotate freely. A welded section 27 where the ball section 23 and the axis section 25 are welded comprises a machined surface 29 that has been cut and the machined surface 29 has a curved first corner part 31. A method for manufacturing said ball joint 10 comprises a welding step for welding a ball section 23a and an axis section 25a, and a cutting step for forming the machined surface 29 by cutting the welded section 27 where the ball section 23a and the axis section 25a have been welded. The cutting step performs a process that includes a step for forming the curved first corner part 31 on the machined surface 29. As a result, it is possible to obtain a ball joint with a large swing angle.