There is provided an ozone generating apparatus that requires no use of cooling water, is small in size and easy in maintenance. The ozone generating apparatus includes a ground electrode 1 formed of a substantially cylindrical metal tube, and a high voltage electrode 5 having a substantially cylindrical dielectric body substantially concentrically arranged inside the ground electrode, and having a high voltage applied to an electrically conductive layer 6 formed on an inner peripheral surface thereof, in which an oxygen-containing gas is supplied into an electric discharge gap formed between the ground electrode and the high voltage electrode to generate ozone, wherein the ground electrode is formed integrally with plural air cooling fins 2 extending in a longitudinal direction at an outer peripheral side thereof.