A guidewire catheter (1) includes: a sheath (6) for passing a guidewire (5) therethrough an operation section (3) connected to an end of the sheath (6) and having a through-hole (7c) for passing the guidewire (5) therethrough a guidewire adapter (4) connected to the operation section (3) and capable of freely extending or retracting relative to the operation section (3) along the axial line of the through-hole (7c), the guidewire adapter (4) grasping the outer periphery surface of the guidewire (5) projecting from the through-hole (7c), and the guidewire adapter (4) being capable of guiding and moving the guidewire (5) relative to the operation section in an axial direction and a circumferential direction of the through-hole (7c).
