Each of a plurality of segments for a vibration propagating member corresponds to a half wavelength part between two antinodes adjacent to each other and is symmetrical with respect to the longitudinal direction centered on a node between the antinodes. In each of a plurality of recessed segments within the segments, the node is positioned in a groove, and an intermediate extending part extends from the base side of the groove to the tip side thereof for the longitudinal direction. For at least two of the recessed segments, the dimension for the longitudinal direction of the intermediate extending part and/or the area of the cross-section perpendicular to the longitudinal direction of the intermediate extending part differs from each other.
