An ozone-generating system provided with: an ozone-generating device (3), which has a discharge electrode (30) that forms a discharge space (305); a gas supply device (1); a power source device, which supplies electric power to the discharge electrode (30); a temperature adjustment device (7), which adjusts the temperature of the discharge electrode (30); a control unit (4), which controls the operation of the ozone-generating device (3); and a detection unit (25), which detects an ozone generation parameter (Di) in the ozone-generating device (3). On the basis of the value of the ozone generation parameter (Di) output from the detection unit (25), the control unit (4) switches from a normal operation mode to a cleaning operation mode, in which the temperature adjustment device (7) and the gas supply device (1) or the temperature adjustment device (7) and the power source device are cooperatively controlled and the temperature of the discharge electrode (30) is raised to a temperature at which dinitrogen pentoxide is vaporized to clean the surface of the discharge electrode (30) and the discharge space (305) while continuing to generate ozone in the discharge space (305).