The aim of the present invention lies in providing a catheter balloon (11) which has improved pressure resistance in a film as a whole and a balloon catheter (10). A tubular catheter balloon (11) is formed from a film comprising a lamination of at least two layers comprising a polyamide elastomer layer (8) and a polyamide layer (9). The polyamide elastomer layer (8) is provided inside the polyamide layer (9). The refractive index n in the circumferential direction of the section perpendicular to the axis on the inside surface of the polyamide layer (9) is greater than the refractive index n in the circumferential direction of the section perpendicular to the axis on the inside surface of the polyamide elastomer layer (8) and the difference between the refractive index n and the refractive index n is at least 0.01.
