An ultrasound horn is provided which vibrates a bonding tool, attached at a tip, in a plurality of directions with a simple structure. There is provided an ultrasound horn having: a longitudinal vibration generator; a horn portion; and a torsional vibration generator. The torsional vibration generator includes a body including a polygonal pillar portion, second layered elements in which a plurality of second piezoelectric elements are layered, and which are attached to side surfaces of the polygonal pillar portion, weights, and a pressure application ring which applies a pressure by pressing the second piezoelectric elements against the polygonal pillar portion via the weights.