Provided is an ozone generator for generating ozone using high voltage discharging between an electrode plate forming a first electrode and a heat sink forming a second electrode. The ozone generator includes: an inner tube and a middle tube each of which is concentrically disposed, the electrode plate being interposed between the inner tube and the middle tube; an adhesive sealing both ends of the electrode plate; an electrode pipe for electrically connecting to a power source and disposed within the electrode plate; a passage formed through a middle of the heat sink; and an outer tube installed in an inner periphery surface of the passage, the outer tube being concentrically disposed to maintain a predetermined distance from an outer periphery surface of the middle tube.