High-pressure treatment apparatus and method for operating high-pressure treatment apparatus

An object of the present invention is to continuously feed an object to be treated to a high-pressure reactor which treats the object to be treated containing 10 mass % or more of water under high pressure, while preventing backflow of a high-pressure atmosphere from the high-pressure reactor. This is embodied by making a configuration such that the object to be treated is fed to the high-pressure reactor connected to a discharge port of a screw feeder which is provided with a feed unit for the object to be treated and the discharge port on one end side and the other end side respectively and forms a high-pressure atmosphere pressurized to, for example, 2 MPa or higher, while air-tightness between the high-pressure atmosphere and the one end side of the screw feeder is maintained by a sealing action of an accumulation compressed on the other end side of the screw feeder.