The present invention aims to provide a catheter balloon with improved pressure resistance of the entire membrane and a balloon catheter. The present invention is a cylindrical catheter balloon formed of a membrane as a laminate of at least two layers including a polyamide elastomer layer and a polyamide layer, in which the polyamide elastomer layer is disposed at the inner side of the polyamide layer, a refractive index n r1 in the circumferential direction of a cross-section perpendicular to the axis in the surface of inner side of the polyamide layer is greater than a refractive index n r2 in the circumferential direction of a cross-section perpendicular to the axis in the surface of inner side of the polyamide elastomer layer, and a difference between the refractive index n r1 and the refractive index n r2 is 0.01 or greater.
