Abstract: A small volume rotative welding gun comprises a welding torch which is adjustable both radially and angularly with respect to a movable block, a flat torque motor and a movable block having an accessible front portion carrying the welding torch so as to put same in alignment with a workpiece to be welded. A rear portion of the block passes through the flat motor and is connected to the motor rotor and is provided with axially extending electric wires. The block has a cooling fluid inlet and an inlet for a protective gas flow, both of the inlets being co-axial with said electric wires, and an insulating member. Also provided is a body in which the flat motor is fixed which comprises a device for measuring rotations, liquid metal or carbon electric contacts, bearings for centering the movable block, a protective hood, and gas and current stationary outlets. A ring is further provided for fixing the body to a support member for positioning the gun comprising a device for axially adjusting the gun.