A catheter balloon and a balloon catheter in which compliance characteristics of a membrane are improved in its entirety. The catheter balloon includes a membranous body that can dilate and contract by fluid supplied from a catheter. The membranous body includes an intermediate layer which is formed of a non-elastomer, an outer layer which is arranged on an outer surface of the intermediate layer and contains an elastomer, and an inner layer which is arranged on an inner surface of the intermediate layer and contains an elastomer. The average wall thickness of the intermediate layer is within 30% to 70% of the wall thickness of the balloon in its entirety.
