While in the ultrasonic probe to perform an acoustic lens for beam focusing ultrasound, in a sealed casing part to be the entry and exit surface of the ultrasonic wave is made of a material having good sound transmission properties, the speed of sound is different and in a mutually insoluble least There were housed in a state in which the other is laminated on the wave transmission and reception direction while forming an interface between the liquid layers of two types of insulating an electrically conductive, and further covered with an insulating layer around a liquid layer of the two In addition to arranging the non-contact electrodes cracked, established a contact electrode in conductive contact with the conductive liquid layers, the focus of the acoustic lens and by changing the interface shape by applying voltage to the contact between the electrodes and the non-contact electrode variable.超音波のビーム収束を音響レンズで行う超音波探触子において、少なくとも超音波の入出射面となる部分が音響透過性の良好な材質からなる密閉ケーシングに、互いに不溶で音速が異なり、かつ一方が導電性で他方が絶縁性の2種類の液体層を、間に界面を形成しながら上記送受波方向に積層する状態で収容し、さらに、その2種類の液体層の周囲に絶縁層で覆われた非接触電極を配置するとともに、上記導電液体層に導電接触する接触電極を設置し、上記非接触電極と上記接触電極間への電圧印加により上記界面形状を変化させて音響レンズの焦点を可変する。
