A balloon catheter (1) including: a flexible sheath (2) which has at least one lumen and a cylindrical balloon (3) which is fixed to the outer peripheral surface of the sheath (2) and can be inflated with a fluid supplied from the lumen wherein the sheath (2) has a large diameter portion (7) whose outer diameter is greater than a basic outer diameter (D1) thereof, and the balloon (3) is set to have a maximum inner diameter greater than the basic outer diameter (D1) when deflated, and is attached to the outer peripheral surface of the large diameter portion (7).
