[PROBLEMS TO BE SOLVED]An object of the present invention is to provide a medical device in which an incising member is not likely to come off upon radial expansion or radial contraction of an expandable-and-contractible member and the incising member is not likely to interfere with the expanding or contracting movement of the expandable-and-contractible member.[SOLUTION]A medical device 1 has a configuration where a distal end 11 of an expandable-and-contractible member 10 and a distal end 21 of an incising member 20 are fixed to a distal tip 40, a proximal end 12 of the expandable-and-contractible member 10 and a proximal end 33 of a core wire 30 are fixed to a ring 50, the core wire 30 is inserted in a hollow portion 22 of the incising member 20 from a proximal end direction, and the core wire 30 can slide in the longitudinal direction within the hollow portion 22 as the expandable-and-contractible member 10 expands or contracts. Owing to the presence of the core wire 30 inserted in the hollow portion 22, the incising member 20 does not come off the expandable-and-contractible member 10 as the expandable-and-contractible member 10 expands or contracts and can slide to an optimum position. As a result, the possibility of the incising member 20 interfering with the radial expansion or the radial contraction of the expandable-and-contractible member 10 can be reduced. The core wire 30 can be pulled out of the hollow portion 22 of the incising member 20 (in other words, the core wire 30 and the incising member 20 can become separated from each other), so that the load (external force) applied on the incising member 20 by the stenosis or stricture that is caught can be reduced, consequently reducing the possibility of the incising member 20 coming off.
