An ultrasonic treatment device comprising: a vibration transmitting section which extends from a proximal direction toward a distal direction along a longitudinal axis, a hole-shaped portion being defined inside a cylindrical portion forming a distal end portion of the vibration transmitting section, the hole-shaped portion extending toward the proximal direction by a hole defining surface, a distal end of the hole-shaped portion being open to an outside of the vibration transmitting section; and a tube member which has a tube distal end, the tube distal end of the tube member being connected to the hole defining surface of the vibration transmitting section in the hole-shaped portion, the tube member extending from the tube distal end through the hole-shaped portion toward the proximal direction inside the vibration transmitting section, the tube member being extended from the inside of the vibration transmitting section to the outside of the vibration transmitting section at a position located to a proximal direction side with respect to a position where the distal end is connected to the hole defining surface, an inside of the tube member communicating with the distal end of the hole-shaped portion, the vibration transmitting section including a piezoelectric element which is provided in a proximal portion of the vibration transmitting section and located to the proximal direction side with respect to the position where the tube distal end is connected to the hole defining surface, the piezoelectric element being configured to generate an ultrasonic vibration and thereby configured to transmit the generated ultrasonic vibration to the distal end portion of the vibration transmitting section through the vibration transmitting section, wherein the vibration transmitting section is configured to vibrate by the generated ultrasonic vibration so that a first node position that is a node position of the ultrasonic vibration is located at the position where the tube distal end is connected to the hole defining surface, and thereby the ultrasonic vibration is prevented from being transmitted from the transmitting section to the tube member at the position where the tube distal end is connected to the hole defining surface. a vibration transmitting section which extends from a proximal direction toward a distal direction along a longitudinal axis, a hole-shaped portion being defined inside a cylindrical portion forming a distal end portion of the vibration transmitting section, the hole-shaped portion extending toward the proximal direction by a hole defining surface, a distal end of the hole-shaped portion being open to an outside of the vibration transmitting section; and a tube member which has a tube distal end, the tube distal end of the tube member being connected to the hole defining surface of the vibration transmitting section in the hole-shaped portion, the tube member extending from the tube distal end through the hole-shaped portion toward the proximal direction inside the vibration transmitting section, the tube member being extended from the inside of the vibration transmitting section to the outside of the vibration transmitting section at a position located to a proximal direction side with respect to a position where the distal end is connected to the hole defining surface, an inside of the tube member communicating with the distal end of the hole-shaped portion, the vibration transmitting section including a piezoelectric element which is provided in a proximal portion of the vibration transmitting section and located to the proximal direction side with respect to the position where the tube distal end is connected to the hole defining surface, the piezoelectric element being configured to generate an ultrasonic vibration and thereby configured to transmit the generated ultrasonic vibration to the distal end portion of the vibration transmitting section through the vibration transmitting section, wherein the vibration transmitting section is configured to vibrate by the generated ultrasonic vibration so that a first node position that is a node position of the ultrasonic vibration is located at the position where the tube distal end is connected to the hole defining surface, and thereby the ultrasonic vibration is prevented from being transmitted from the transmitting section to the tube member at the position where the tube distal end is connected to the hole defining surface.