Abstract: In an apparatus of manufacturing diaphragms, a layer of a difficulty flowable metal powder is applied to a support, a wire net is rolled onto the powder layer and the latter is compacted at the same time and the metal powder is fired at 800.degree. to 1500.degree. C. in an oxidizing atmosphere. In order to impart to the diaphragms a constant thickness, strength and density, the metal powder is uniformly distributed and applied as regards its bulk volume to the support and the powder layer is moved under a distributing roller rotating opposite to the direction in which the powder is fed.