Provided is a treatment device capable of improving convenience during treatment. The treatment device 4 includes: a catheter 1 that has a delivery shaft 11 which extends along an axial direction (Z axis direction); a stent graft 2 that has a graft 22 and a stent 21, which are cylindrical, and that has a stent disposed region A41 and a stent non-disposed region A42 along the axial direction; and a cover 3 for maintaining the stent graft 2 in a diameter-reduced state at a distal region A1 of the delivery shaft 11. The cover 3 includes: a cylindrical outer layer portion 32; an inner layer portion 31 which is positioned inboard of the outer layer portion 32 and maintains the stent graft 2 in the diameter-reduced state inboard thereof; a folded portion 33 which connects the outer layer portion 32 to the inner layer portion 31 at the distal end side of the delivery shaft 11; and markers 31M which are disposed on the inner layer portion 31 in a region facing the stent non-disposed region A42 and which are visible from outside through the outer layer portion 32.本發明提供一種可以提升治療時的便利性的治療裝置。治療裝置4具備:導管1,其具有沿著軸向(Z軸方向)延伸的傳送軸11;覆膜支架2,其以包括管狀移植物22及支架21的方式構成,並且沿著軸向具有支架配置區域A41及支架未配置區域A42;以及蓋件3,其用於在傳送軸11的前端區域A1使覆膜支架2保持在收縮狀態。蓋件3具有:筒狀的外層部32;內層部31,位於外層部32的內周側,並且在自身的內周側覆膜支架2以收縮狀態保持;折返部33,其在傳送軸11的前端側,連接外層部32與內層部31;以及標記31M,其以配置於內層部31的與支架未配置區域A42對向的區域,並且可以透過外層部32從外部視認的方式構成。