[Object] Provided is an expansible catheter balloon that has a spreadable outer diameter controllable easily in treatments for a calcific aortic stenosis, rheumatic and congenital aortic stenoses and others, and that can be effectively prevented from being freely shifted and can easily be fixed at a predetermined position. [Solution] The catheter balloon 10 includes a balloon 20 having shoulder parts 23 made of a non-expansible material or made low-expansible and an expandable waist part 30, and a catheter having a catheter body 70 to which this balloon 20 is fitted.
