PROBLEM TO BE SOLVED: To provide a balloon catheter which can be moved smoothly in a living body lumen, and in which push-in properties of an expansion part into a narrow part have been improved.SOLUTION: A balloon catheter includes: a long-sized flexible shaft 110 provided with an outer tube 111 having a lumen and an inner tube 112 disposed in the lumen of the outer tube； an expansion part 120 which can expand and contract accompanying inflow and outflow of fluid F, the tip of which is fixed to the tip of the inner tube, and the base end part of which is fixed to the tip of the outer tube； an expansion lumen 115 formed between the outer peripheral surface of the inner tube and the inner peripheral part of the outer tube, in which the fluid can circulate； and a fluid adjustment part 130 for controlling the movement of the fluid in the expansion lumen. The fluid adjustment part transits from a first state in which a part between the expansion lumen and the expansion part is closed to a second state in which the expansion lumen is communicated with the expansion part when the fluid is injected in the expansion lumen and the internal pressure of the expansion lumen exceeds a predetermined value.SELECTED DRAWING: Figure 2【課題】生体管腔での円滑な移動を可能とし、さらに狭窄部内への拡張部の押し込み性が向上されたバルーンカテーテルを提供する。【解決手段】内腔を有する外管１１１および外管の内腔に配置された内管１１２を備えた可撓性のある長尺状のシャフト１１０と、先端部が内管の先端部に固定され、かつ、基端部が外管の先端部に固定されており、流体Ｆの流入および排出に伴い拡張および収縮可能な拡張部１２０と、内管の外周面と外管の内周面との間に形成されており、流体が流通可能な拡張ルーメン１１５と、拡張ルーメン内の流体の移動を制御する流体調整部１３０と、を有する。流体調整部は、拡張ルーメンと拡張部との間を閉鎖する第１状態から、拡張ルーメンに流体を注入して拡張ルーメンの内圧が所定値を超えた際に、拡張ルーメンと拡張部との間を連通する第２状態に移行する。【選択図】図２
