A capturing unit provided on a distal end of a second tube can be deformed into a contracted state and an expanded state, in which the capturing unit is deployed to form a capturing chamber. The capturing chamber has an opening area decreased as it goes from a distal end opening of the capturing chamber toward a proximal end opening of the capturing chamber. A third tube rotatable relative to the second tube and a cutting unit provided on a distal end of the third tube for cutting a foreign substance are arranged in a second lumen. In the expanded state of the capturing unit, the cutting unit is arranged more toward the proximal end opening of the capturing chamber than the distal end opening.
