To adjust the weaving width with simple constitution.

In a welding equipment, a swinging width adjusting device 4 to be arranged between a torch holder 6 to support a welding torch and a torch drive motor 3 comprises an eccentric ring to be driven in a casing by the torch drive motor 3, a first slider block 9 to be driven straight by the eccentric ring, a second slider block 10 to be driven straight by the first slider block 9, and a swinging arm 11 to be swing by the second slider block 10. The first slider block 9 is rotatably supported relative to the casing, and the second slider block 10 is fixed to the casing. By turning the first slider block 9 to the second slider block 10, the swinging range of the swinging arm 11 is changed to adjust the weaving width of the welding torch.