An ozone generator includes a container, a first metal electrode, a dielectric electrode, a heat pipe, a heat sink, and a power supply unit. The first metal electrode is a cylindrical electrode the axial direction of which is a first direction, and disposed in the container. A cooling medium is supplied to an outer peripheral surface thereof. The dielectric electrode is a cylindrical electrode that is disposed to be opposed to an inner peripheral surface of the first metal electrode, and is coaxial with the first metal electrode. The heat pipe is disposed to be opposed to an inner peripheral surface of the dielectric electrode, and has electrical conductivity. The heat sink is disposed on the outside as an outer space of a space between the first metal electrode and the heat pipe, and connected to the heat pipe.