To prevent an accident from occurring due to breakage or disconnection by interposing a safety means for disconnection in a flow channel when an abnormal electric current flows through the flow channel of the electric current at the time of connecting an electrode on the high voltage side in a container through a lead-out terminal to a pulse power electrode.

A cylindrical electrode 10 on the ground contact side is housed in the interior of a pressure container 8 and an electrode 13 on the high voltage side is arranged at a shaft center position of the electrode 10 on the ground contact side. The electrode 13 on the high voltage side is connected through an introduction terminal 15 in a state maintaining insulation passing through the pressure container 8 to a pulse power electrode with cables 14 and 16 to constitute an ozonizer 7. In the ozonizer 7, e.g. a fuse 23 as a safety means for disconnecting a flow channel of an electric current when an abnormal electric current flows is connected in the course of the cable 14. Thereby, the abnormal electric current flows through the fuse 23 to disconnect the flow channel when the electrode 13 on the high voltage side is broken and short-circuited. As a result, an overcurrent is prevented from flowing through the ozonizer 7.