Abstract: There can be provided a spot welding gun in which a gun arm can be detachably attached to a gun main body, capable of conducting welding operation without increase in size and with good precision. Coupling portions 7 used to attach/detach the gun arm 9 having the fixed electrode 13 to/from the gun main body 1 having the pressure electrode 11 comprise an insertion recess portion which is formed on the gun main body 1 side to be tapered along the direction perpendicular to pressure direction of the pressure electrode 11, and an insertion portion which is formed on the gun arm 9 side to be tapered along the direction perpendicular to the pressure direction for easy insertion into the insertion recess portion.

Abstract: A spot welding apparatus comprises a welding gun having a pair of opposing welding electrodes either one of which is movable towards the other to apply a pressure onto a work and away from the other to release the pressure, a servomotor attached to the welding gun for adjusting the pressure applied to the work through movement of the movable welding electrode, a servomotor controller for controlling an operation of the servomotor, a welding current regulator for adjusting a value of welding current applied through the opposing electrodes to the work, a weld-interval timer arranged for adjusting at least one weld time interval and weld timing for the welding current and the pressure both applied to the work, and a spot welding controller electronically connected to the servomotor controller, the welding current regulator and the weld-interval timer, for simultaneously and arbitrarily adjusting a welding condition, namely the welding current, the pressure, the weld time interval and the weld timing, during a cy