A medical device includes an expandable-and-contractible member capable of radially expanding and radially contracting, an incising member disposed on an outer circumference of the expandable-and-contractible member and having a hollow portion, a core wire inserted in the hollow portion, a distal tip, and a ring. The core wire is capable of sliding in a longitudinal direction of the medical device as the expandable-and-contractible member expands or contracts. The incising member is therefore not likely to come off upon radial expansion or radial contraction of the expandable-and-contractible member, and is therefore not likely to interfere with the expanding or contracting movement of the expandable-and-contractible member.
