An ultrasonic actuated unit comprising: an ultrasonic transmitting portion which extends along a longitudinal axis and which is configured to perform a longitudinal vibration having a vibration direction parallel to the longitudinal axis at a predetermined reference frequency when an ultrasonic vibration is transmitted from a proximal direction toward a distal direction; an intermediary portion which is continuous with the ultrasonic transmitting portion or connected to the ultrasonic transmitting portion at a node position (N1; N2) of the longitudinal vibration; a noncontact vibrating portion which extends in directions (C1,C2) parallel to the longitudinal axis without contacting the ultrasonic transmitting portion, the noncontact vibrating portion being continuous with the intermediary portion or connected to the intermediary portion whereby an undesired vibration is transmitted to the noncontact vibrating portion from the ultrasonic transmitting portion via the intermediary portion, the undesired vibration having a vibration direction which is not parallel to the longitudinal axis, the noncontact vibrating portion having an axially parallel dimension different in value from a natural number multiple of a half wavelength of the longitudinal vibration at the reference frequency in the directions (C1,C2) parallel to the longitudinal axis so that the noncontact vibration portion does not perform the longitudinal vibration at the reference frequency when the ultrasonic vibration is transmitted via the intermediary portion; and a vibration absorbing portion which is attached to the noncontact vibrating portion and which is configured to absorb the undesired vibration transmitted to the noncontact vibrating portion. an ultrasonic transmitting portion which extends along a longitudinal axis and which is configured to perform a longitudinal vibration having a vibration direction parallel to the longitudinal axis at a predetermined reference frequency when an ultrasonic vibration is transmitted from a proximal direction toward a distal direction; an intermediary portion which is continuous with the ultrasonic transmitting portion or connected to the ultrasonic transmitting portion at a node position (N1; N2) of the longitudinal vibration; a noncontact vibrating portion which extends in directions (C1,C2) parallel to the longitudinal axis without contacting the ultrasonic transmitting portion, the noncontact vibrating portion being continuous with the intermediary portion or connected to the intermediary portion whereby an undesired vibration is transmitted to the noncontact vibrating portion from the ultrasonic transmitting portion via the intermediary portion, the undesired vibration having a vibration direction which is not parallel to the longitudinal axis, the noncontact vibrating portion having an axially parallel dimension different in value from a natural number multiple of a half wavelength of the longitudinal vibration at the reference frequency in the directions (C1,C2) parallel to the longitudinal axis so that the noncontact vibration portion does not perform the longitudinal vibration at the reference frequency when the ultrasonic vibration is transmitted via the intermediary portion; and a vibration absorbing portion which is attached to the noncontact vibrating portion and which is configured to absorb the undesired vibration transmitted to the noncontact vibrating portion.