An ultrasonic treatment device including, a vibration transmitting portion, an inner surface which defines an internal space, a first tube which extends along the longitudinal axis in an internal space, a path portion which is provided on the inner circumferential side of the first tube, and a first spacer which intervenes between the inner surface and the first tube at a node position of the ultrasonic vibration in a longitudinal axis and which supports the first tube so that the outer circumferential surface of the first tube does not contact the inner surface.
