PROBLEM TO BE SOLVED: To provide a device which can expand and contract an expansion part in an appropriate state by simple operation.SOLUTION: A medical device 10 includes: a long outer tube 40； an inner tube 20 which passes through the inside of the outer tube 40 and protrudes to a distal side with respect to the outer tube 40； a plurality of wire parts 31 which are positioned between a distal part of the outer tube 40 and a distal part of the inner tube 20 and extend in an axial direction of the inner tube 20； an expansion part 30 which bends in a circumferential direction by moving the inner tube 20 in the axial direction with respect to the outer tube 40 to be expandable； a biasing member 80 which is arranged inside of the outer tube 40 and biases the inner tube 20 in a proximal direction with respect to the outer tube 40； a fixing part which can fix positions of the inner tube 20 and the outer tube 40 while the expansion part 30 is expanded by moving the inner tube 20 in the axial direction with respect to the outer tube 40 in a manner to suppress the biasing force of the biasing member 80； and a pressing part 60 which can release the fixed state of the fixing part by pressing in a prescribed direction.SELECTED DRAWING: Figure 2【課題】簡便な操作で、拡張部を適切な状態へ拡張させ、かつ収縮させることが可能なデバイスを提供する。【解決手段】長尺な外管４０と、外管４０の内部を通り、外管４０よりも遠位側へ突出する内管２０と、外管４０の遠位部および内管２０の遠位部の間に位置し、内管２０の軸方向に沿って延びる複数の線材部３１を備え、内管２０を外管４０に対して軸方向へ移動させることで周方向に撓んで拡張可能な拡張部３０と、外管４０の内部に配置され、内管２０を外管４０に対して近位方向へ付勢する付勢部材８０と、付勢部材８０の付勢力を抑制するように内管２０を外管４０に対して軸方向へ移動させて拡張部３０が拡張した状態において、内管２０および外管４０の位置を固定可能な固定部と、固定部における固定状態を所定の方向へ押圧することで解除可能とする押圧部６０と、を有する医療デバイス１０である。【選択図】図２
