An ultrasonic transducer element chip includes a substrate, ultrasonic transducer elements and a reinforcing member. The substrate defines openings arranged in an array pattern. The ultrasonic transducer elements are respectively disposed at the openings on a first surface of the substrate. The reinforcing member is fixed on a second surface of the substrate opposite to the first surface of the substrate. The reinforcing member includes linear groove parts formed on a surface of the reinforcing member fixed on the substrate so that internal spaces of the openings and an external space of the substrate are in communication with each other via the linear groove parts. The linear groove parts extend along a plane of the surface of the reinforcing member, and they are arranged at an interval in a first direction smaller than a width of each opening on the second surface of the substrate in the first direction.本發明之超音波轉換器元件晶片之特徵在於包含:基板,其開口配置成陣列狀;超音波轉換器元件,其於上述基板之第1面設置於各個上述開口;及加強構件,其固定於上述基板之與上述第1面相反側之上述基板之第2面而加強上述基板;上述加強構件係於固定於上述基板之上述第2面之面包含直線狀凹槽部,該直線狀凹槽部於該面之面內之第1方向上,以較上述基板之上述第2面之上述開口之上述第1方向之開口寬度小之間隔並排配置,並將上述開口之內部空間及上述基板之外部空間相互連通。17‧‧‧元件晶片21‧‧‧基板21a‧‧‧第1邊21b‧‧‧第2邊22‧‧‧元件陣列23‧‧‧元件24‧‧‧下部電極24a‧‧‧第1導電體25‧‧‧上部電極25a‧‧‧第2導電體26‧‧‧壓電體膜27‧‧‧引出配線29‧‧‧直線31‧‧‧周緣區域32a‧‧‧第1端子陣列32b‧‧‧第2端子陣列33‧‧‧下部電極端子34‧‧‧上部電極端子35‧‧‧下部電極端子36‧‧‧上部電極端子37‧‧‧第1軟性印刷基板38‧‧‧第1信號線41‧‧‧第2軟性印刷基板42‧‧‧第2信號線
