An ultrasonic transducer element comprising: a substrate a lower electrode formed on a first main surface of the substrate a first insulating film formed on the lower electrode and a second insulating film formed on the first insulating film A first insulating layer formed on the first cavity layer an upper electrode formed on the second insulating layer and disposed at a position overlapping with the first cavity layer when viewed from the upper surface A third insulating film formed on the upper electrode a second hollow layer formed on the third insulating film a fourth insulating film formed on the second hollow layer A fixed portion made of the second to fourth insulating films surrounding the outer circumference of the first hollow layer as seen from the upper surface of the one main surface, and a second portion including the second to fourth insulating films formed on the first hollow layer and the upper electrode A movable portion which becomes an area inside the second hollow layer in the membrane made of the movable portion and the movable portion, As a connection portion made of the second to fourth insulating film to connect the tough, a first connection portion, and constitute a second connecting portion which are laminated at a and spacing said first connection part.超音波トランスデューサ素子を、基板と、前記基板の第1主面上に形成された下部電極と、前記下部電極上に形成された第1絶縁膜と、前記第1絶縁膜上に形成された第1空洞層と、前記第1空洞層上に形成された第2絶縁膜と、前記第2絶縁膜上に形成され、上面からみて前記第1空洞層と重なる位置に配置された上部電極と、前記上部電極上に形成された第3絶縁膜と、前記第3絶縁膜上に形成された第2空洞層と、前記第2空洞層上に形成された第4絶縁膜と、前記基板の第1主面の上面からみて、前記第1空洞層外周を取り囲む前記第2~4絶縁膜より成る固定部と、前記第1空洞層上に形成された前記第2~4絶縁膜と前記上部電極より成るメンブレンにおいて、前記第2空洞層より内側の領域になる可動部と、前記可動部と前記固定部を接続する前記第2~4絶縁膜より成る接続部として、第1接続部と、該第1接続部と間隔を隔てて積層された第2接続部とを備えて構成した。
