The description refers to an electrostatically operated diaphragm pump comprising a first pump body acting as the counterelectode body and a second pump body which has a diaphragm region. The two pump bodies together define a cavity bordering the diaphragm region and are electrically isolated from each other. The cavity is filled with a medium different from the fluid to be pumped. The pump bodies can consist of a semiconductor material of different charge types. The medium located in the cavity preferably has a large dielectric constant.