As from the piezoelectric oscillator backing layer it is attenuated the ultra wave which (1) is emitted on the rear effectively with (4), the piezoelectric oscillator (1) making the reflected wave decrease which returns to side, it actualizes the ultrasonic probe whose sensitivity is good, furthermore makes the thickness of backing layer decrease 4 more substantially than past. The ultra wave where the piezoelectric oscillator which gives out the ultra wave (1) and the piezoelectric oscillator (1) it is connected by the rear, the piezoelectric oscillator (1) with the phase of opposite to front direction the piezoelectric oscillator the ultra wave where (1) is emitted in rear direction the backing layer which is attenuated it has (4), as for backing layer (4), the plural acoustic tubes where the length which is based on the principle of superposition of the sound wave differs it arranges in the direction which matches the traveling direction to ultrasonic front direction and the rear direction which (5), that longitudinal direction, are given out from the piezoelectric oscillator (1), the acoustic tube as for (5), the piezoelectric oscillator (1) backing layer (4) is emitted on side, the wholeOr it is attenuated partly in the mark.圧電振動子(1)から背面に放射された超音波をバッキング層(4)で効果的に減衰させると共に、圧電振動子(1)側に戻る反射波を低減させて、感度のよい超音波探触子を実現し、さらにバッキング層4の厚さを従来よりも大幅に低減させる。超音波を発する圧電振動子(1)と、圧電振動子(1)の背面に接合され、圧電振動子(1)の前面方向とは逆の位相で圧電振動子(1)の背面方向に放射された超音波を減衰するバッキング層(4)とを備え、バッキング層(4)は、音波の重ね合わせの原理に基づく長さの異なる複数の音響管(5)を、その長手方向が、圧電振動子(1)から発せられる超音波の前面方向および背面方向への進行方向と一致する向きに配置し、音響管(5)は、圧電振動子(1)がバッキング層(4)側に放射された超音波を、全体的にまたは部分的に減衰する。
