The invention describes a method for producing a balloon from a suitable blank, wherein the blank is introduced into an outer mold, comprising the following steps: the blank is heated in a first step and is acted on with pressure in such a way that it expands until against the inner wall of the outer mold, the pressure is reduced in a second step following expansion of the blank, such that the blank relaxes again, the three-dimensional expansion of the mold is changed in a third step, and the blank is acted on again with pressure in a fourth step, such that it expands again until against the inner wall of the changed volume of the outer mold.
