A welding device comprising a body having a cylindrical portion and an integral gripping portion extending away from the cylindrical portion. A welding head is provided at one end of the cylindrical portion. The welding head is angularly displaceable relative to the cylindrical portion about the longitudinal axis of the cylindrical portion and supports an ultrasonic transducer and an anvil co-operable with the transducer. The transducer and anvil are relatively movable towards one another to pinch an object to be welded therebetween. A pulling device operable by a trigger is provided for pulling the transducer and the anvil towards one another and a battery pack is releasably attached to the gripping portion.