In a method for producing a membrane filter for a fluid purifier, wherein the filter includes a pair of membrane layers and a spacer layer placed therebetween, it is proposed, among other things, that a layer of membrane-forming casting solution is applied to the outer surfaces of a web of fluid-permeable starting material (30) for the membrane layers and the spacer layer, and that the web-like starting material is passed through a bath (90) so as to gel the casting solution. The invention also relates to a membrane filter produced in accordance with the method.