Insertion portion rigidity changeable catheter with balloon

An insertion portion rigidity changeable catheter with a balloon is characterized by comprising a catheter insertion portion having a sheath main body at a front end portion and a basic end portion, a length axis being defined in a direction connecting the front end portion with the basic end portion; a sliding member having a front end and a basic end, being slidably arranged at the basic end side of the sheath main body in the direction of the length axis, and having holding portions and moving in the direction of the length axis according to the operation of the holding portions; and a mechanism which is arranged on the sheath main body, is a spiral member abutting against the front end side of the sliding member in a manner capable of action along with the sliding member, and moves in the direction of the length axis with the sliding of the sliding member. The hardness of the catheter insertion portion is changed corresponding to the movement of the mechanism.