A balloon catheter comprising a balloon formed of a film with a predetermined thickness, the balloon comprising an inflation/deflation portion that is inflatable and deflatable, wherein the film is provided with a linear projection projecting in a thickness direction and extending along a surface of the film at the inflation/deflation portion, and an inner projection projecting inside the balloon in the thickness direction is provided as the projection; wherein the inflation/deflation portion comprises: a straight tube portion having a maximum diameter during inflation; and a pair of tapered portions provided on opposite sides across the straight tube portion in an axial direction of the balloon , the tapered portions each being reduced in diameter toward a side away from the straight tube portion , the film is provided with the projection at each of the straight tube portion and the tapered portions , an outer projection projecting outside the balloon is provided as the projection at the straight tube portion while no inner projection projecting inside the balloon is provided at the straight tube portion , and the inner projection is provided as the projection at at least either one of the tapered portions while no outer projection projecting outside the balloon is provided at this tapered portion ; wherein the projection of the straight tube portion and the projection of each of the tapered portions all extend in the axial direction of the balloon along the surface of the film; and wherein the projection of the straight tube portion extends throughout the straight tube portion in the axial direction, the projection of the straight tube portion is provided in an orientation where one of corners thereof projects radially outside of the balloon , the projection of each of the tapered portions extends throughout the tapered portion in the axial direction, and the projection of the straight tube portion and the projection of each of the tapered portions are provided at a same position in a circumferential direction of the balloon . the film is provided with a linear projection projecting in a thickness direction and extending along a surface of the film at the inflation/deflation portion, and an inner projection projecting inside the balloon in the thickness direction is provided as the projection; a straight tube portion having a maximum diameter during inflation; and a pair of tapered portions provided on opposite sides across the straight tube portion in an axial direction of the balloon , the tapered portions each being reduced in diameter toward a side away from the straight tube portion , the film is provided with the projection at each of the straight tube portion and the tapered portions , an outer projection projecting outside the balloon is provided as the projection at the straight tube portion while no inner projection projecting inside the balloon is provided at the straight tube portion , and the inner projection is provided as the projection at at least either one of the tapered portions while no outer projection projecting outside the balloon is provided at this tapered portion ; wherein the projection of the straight tube portion and the projection of each of the tapered portions all extend in the axial direction of the balloon along the surface of the film; and the projection of the straight tube portion extends throughout the straight tube portion in the axial direction, the projection of the straight tube portion is provided in an orientation where one of corners thereof projects radially outside of the balloon , the projection of each of the tapered portions extends throughout the tapered portion in the axial direction, and the projection of the straight tube portion and the projection of each of the tapered portions are provided at a same position in a circumferential direction of the balloon . <EOS>