Abstract: An ultrasonic-wave delay line element comprises a pentagonal delay medium body formed by cutting at an angle of about 45.degree. a part of the major surface defined by a rectangular shape having two longer sides and two shorter sides, and has a pair of input and output electric-mechanic transducers provided on a side A formed by cutting the major surface. The input and output electric-mechanic transducers are attached to the cut side A at positions near longer side C contiguous to the cut side A with respect to the center of the cut side A; a reflection point for a sound-wave is provided in the cut side A while no reflection point is provided in a shorter side B contiguous to the out side A; two or more reflection points are provided in the longer side C; two reflection points are formed in the other shorter side D isolated from the cut side A; and four or more reflection points are provided in the other longer side E isolated from the cut side A.