Catheter balloon and catheter

To provide a catheter balloon which, when treating calcific aortic stenosis, rheumatic and congenital aortic stenosis, etc., facilitates control of the expanded outer diameter of the stretchable balloon, enables effectively prevention of balloon migration, and can be easily fixed in a prescribed position. This catheter is provided with: a balloon (20) having shoulder sections (23) formed from a non-stretch material or a low-stretching material, and a stretchable waist section (30); and a catheter main body (70) to which the balloon (20) is attached.