A manufacturing method of an absorbent article including a first web which constitutes a front waistband part, and a second web which constitutes a rear waistband part, the method comprising: a step A of conveying the first web and the second web in an overlapped state between an anvil part and a vibrator which are provided to an ultrasonic bonding device; and a step B of bonding predetermined regions provided to the first web and the second web with a predetermined interval in a conveyance direction of the first web and the second web by outputting an ultrasonic vibration from an output part of the vibrator (330 to the predetermined regions, the ultrasonic vibration generated by an oscillator provided to the ultrasonic bonding device, wherein the output part includes: a central output portion configured to output the ultrasonic vibration to a center region of three equal regions into which each predetermined region is divided in a cross direction crossing the conveyance direction; and both-ends output portions configured to output the ultrasonic vibration respectively to both-ends regions of the three equal regions into which each predetermined region is divided, the both-ends regions located at both sides in the cross direction of the center region, step B further comprising outputting a central maximum amplitude of the ultrasonic vibration from the central output portion to the center region smaller than an end maximum amplitude of the ultrasonic vibration outputted from each of the both-ends output portions to a corresponding one of the both-ends regions, and bonding the predetermined regions with a central bonding strength of the center region, bonded by the central output portion, smaller than an end bonding strength of each of the both-ends regions, bonded by a corresponding one of the both-ends output portions. a step A of conveying the first web and the second web in an overlapped state between an anvil part and a vibrator which are provided to an ultrasonic bonding device; and a step B of bonding predetermined regions provided to the first web and the second web with a predetermined interval in a conveyance direction of the first web and the second web by outputting an ultrasonic vibration from an output part of the vibrator (330 to the predetermined regions, the ultrasonic vibration generated by an oscillator provided to the ultrasonic bonding device, wherein the output part includes: a central output portion configured to output the ultrasonic vibration to a center region of three equal regions into which each predetermined region is divided in a cross direction crossing the conveyance direction; and both-ends output portions configured to output the ultrasonic vibration respectively to both-ends regions of the three equal regions into which each predetermined region is divided, the both-ends regions located at both sides in the cross direction of the center region, a central output portion configured to output the ultrasonic vibration to a center region of three equal regions into which each predetermined region is divided in a cross direction crossing the conveyance direction; and both-ends output portions configured to output the ultrasonic vibration respectively to both-ends regions of the three equal regions into which each predetermined region is divided, the both-ends regions located at both sides in the cross direction of the center region, step B further comprising outputting a central maximum amplitude of the ultrasonic vibration from the central output portion to the center region smaller than an end maximum amplitude of the ultrasonic vibration outputted from each of the both-ends output portions to a corresponding one of the both-ends regions, and bonding the predetermined regions with a central bonding strength of the center region, bonded by the central output portion, smaller than an end bonding strength of each of the both-ends regions, bonded by a corresponding one of the both-ends output portions.