PROBLEM TO BE SOLVED: To provide an ultrasonic jointing device which can easily recognize abnormality and trouble thereof when there is abnormality or trouble in pressure measurement means and the like.SOLUTION: An ultrasonic jointing device 10 including an ultrasonic application device 11 having an ultrasonic horn 14 and an anvil 20 sandwiches an object 1A to be bonded between the ultrasonic horn 14 and the anvil 20, applies ultrasonic vibration thereto, and bonds sheets of the object 1A to be bonded. The ultrasonic jointing device comprises: a position control mechanism in which the ultrasonic horn 14 is advanced and retreated toward the anvil 20 so that the ultrasonic horn 14 can be fixed at a specific position in the advancing/retreating direction； and a displacement sensor 28 which detects the position of the ultrasonic horn. The displacement sensor 28 including a first component 28a of the sensor installed at a component interlocked with the ultrasonic horn 14 and a second component 28b of the sensor supported by a support member not interlocked with the ultrasonic horn measures relative distance between the first component 28a of the sensor and the second component 28b of the sensor to detect the position of the ultrasonic horn 14 in the advancing/retreating direction.SELECTED DRAWING: Figure 1
