A medical elongated body is disclosed, which is able to make a nick in a stenosed site and is capable of preferably widening the stenosed site in which the nick is made. A balloon catheter is disclosed, which includes a shaft, a dilation member that is fixed to the shaft on a distal side, and an elastic member that is disposed on an inner surface of the dilation member. The dilation member includes a projection portion, which is a part of the dilation member protruding in a radial direction due to the elastic member disposed at a position where the inner surfaces of the dilation member face each other. A material of the elastic member is configured to be a material, which is further stretched than a material of the dilation member in a circumferential direction when the dilation member dilates.
