An ultrasonic horn (50) includes: a vibration source part (53) to which an ultrasonic vibrator (58) is mounted; a tip end part (56) to which a capillary (18) is mounted; and an intermediate part (54) which is interposed between the tip end part (56) and the vibration source part (53) and propagates vibration generated by the ultrasonic vibrator (58) to the tip end part (56). The intermediate part (54) is formed with a single spiral hole (68) which is a hole penetrating in a radial direction of the ultrasonic horn (50) and advances in an axial direction as the spiral hole advances in a circumferential direction.