The invention relates to a membrane valve, in particular for inhalation devices, comprising a planar membrane made of permanently flexible material, a frame, which has an air opening that is somewhat smaller than the membrane, at least one web, which connects the frame to a retainer that is arranged approximately at the center of the air opening, and a pin, the shaft of which extends through a fastening opening approximately at the center of the membrane and is located in a retaining opening in the retainer, wherein the membrane lies on the frame in the rest state and wherein the pin is spread to form a head, the distance of which to the membrane is small in comparison to the thickness of the membrane or which head lies on the membrane, and the diameter of the shaft near the head is greater than the diameter of the fastening opening,; and the diameter of the shaft at the free end of the shaft is approximately equal to the diameter of the fastening opening.