Problem to be solved: to properly extend the internal positioning device without blocking the blood flow at a predetermined position.An expansion catheter 2 for extending a tubular intravascular insulative material (for example, stent 1) detained in a predetermined position in the blood vessel V is disposed inside an intravascular fixture, and is dilated and dilated to the outside radially outward from the inside of the blood vessel The expansion and contraction member 23 is provided with a pressure reducing member 23, and the expansion and contraction member has a plurality of skeletal main wires 233a,... Each of the plurality of skeletal main wires can be brought into contact with an endodontic member separated from each other in a state of expansion and deformation in the expansion and contraction member.Diagram【課題】血流を遮断することなく血管内留置具の拡張を所定位置で適正に行う。【解決手段】血管V内の所定位置に留置される管状の血管内留置具(例えば、ステント1)を拡張させる拡張用カテーテル2であって、血管内留置具の内側に配され、拡張変形して血管内留置具を内側から径方向外側に押圧する拡縮部材23を備え、拡縮部材は、複数の骨格用主線材233a、…を有し、これら複数の骨格用主線材は、拡縮部材が拡張変形した状態にて、互いに離間して血管内留置具に接触可能である。【選択図】図3
