Abstract: There is provided a servo controller for a spot welding gun for controlling a pressurizing force, applied by a pair of mutually-opposing gun chips, on an object to be welded, including at least one movable gun chip, which is held between the pair of gun chips, by causing a drive source of the movable gun chip to drive the movable gun chip in a direction in order to pressurize the object to be welded. The servo controller includes a feedback control section for calculating a difference value (Fc?F) between an obtained pressurizing-force value F and a required pressurizing-force value Fc, and a feedforward control section for adding a correcting command value, obtained from a position command value or a speed command value for the drive source, to the difference value (Fc?F).