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 nr1 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 nr2 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 nr1 and the refractive index nr2 is at least 0.01.
