To provide an equipment to change the working force by means of a single driving mechanism, and a welding equipment.

With this drive unit 10 which can change the working force, the amount of relative displacement between a fixed member 11 and a movable member 12 makes a working force smaller, when the amount is beyond a prescribed range against a reference positional relationship, in comparison with the one when the amount is within the prescribed range against the reference positional relationship. With this drive unit 10, at least one of the welding units (welding guns) 17 of the welding electrodes is driven.