A membrane valve, with a valve housing, in which a housing interior is formed, in which housing interior a flexible control membrane is arranged. A drive plunger lies opposite a valve seat and the drive plunger has a shank body with a peripheral outer lateral surface. The outer lateral surface of the shank body of the drive plunger at least in the region of a guide section has a polygonally contoured prismatic shaping with a succession of outer side edges and outer side surfaces, wherein the edges and surfaces extend in the plunger longitudinal direction and the succession alternates in the circumferential direction of the drive plunger.