A bonding tool, including: a component mounting unit including a horn that has a heater insertion hole, in which a heater is inserted with a predetermined clearance, and transmits ultrasonic vibration, an ultrasonic transducer that is fixed on the horn and produces the ultrasonic vibration, and an electronic component holder that is fixed on the horn, holds an electronic component and is heated by the heater; a leg that supports the horn on both sides of the horn at nodal points of the ultrasonic vibration on the horn; a supporter that holds the leg; and a heater holder that holds the heater on both sides of the horn, wherein the leg and the heater holder are formed integrally with each other.