To provide an ozone generating system in which the air to be supplied to an ozonizer as a raw material can be dried satisfactorily, which can cope quickly with an unexpected accident such as the sudden stop of a constituent equipment and the installation space of which can be saved as a whole.

This ozone generating system 10 is provided with the ozonizer 1 for producing ozone from air and a membrane drier 2 connected to the upstream side of the ozonizer 1. An air compressor 3 is connected to the upstream side of the drier 2 for sending the compressed air to the drier 2. An after-filter 4 is installed between the compressor 3 and the drier 2 for removing minute contaminants from the compressed air. The drier 2 comprises a hollow fiber membrane 8 for adsorbing only the moisture of the compressed air. A cooling unit 6 is installed at the succeeding stage of the ozonizer 1.