Provided is a treatment apparatus that makes it possible to improve usability in treatment. A treatment apparatus 4 includes a catheter 1 that includes a delivery shaft 11. The delivery shaft 11 extends in an axial direction (a Z-axis direction) and is configured to hold, in a tip end region A1, a stent graft 2 having a reduced diameter. The delivery shaft 11 includes a tube-shaped member 110 that includes one or a plurality of lumens (one or a plurality of lumens L) provided in the axial direction, and a plurality of core members (core members 112a to 112d) that extend in the axial direction inside the tube-shaped member 110 at least in the tip end region A1, and have plastic deformability. The plurality of core members are disposed substantially isotropically in an outer circumferential direction R1 of the lumen L inside the tube-shaped member 110.
