The diaphragm machine belongs to a positive displacement compressor, which is to change the volume of the air chamber by diaphragm deformation to achieve compression of the gas. A curved surface is formed on the cylinder head and the oil distribution plate of the membrane head of the diaphragm, and the diaphragm sandwiched between the two forms an air chamber and an oil chamber respectively, and the air chamber and the suction chamber are installed in the valve hole of the cylinder head. The exhaust valve communicates with each other, and the oil chamber communicates with the oil chamber in the cylinder through a plurality of flow guiding holes on the oil distribution plate, and the bolt around the film head fastens the cylinder head, the diaphragm, the oil distribution plate and the cylinder body. Together, the air chamber and the oil chamber in the membrane head are sealed without leakage.