To provide a high-pressure heat treat furnace, which has a high cooling capacity to enable the shortening of the cycle time, and a simple and economical structure.

This high-pressure heat treatment furnace comprises a pressure vessel 3 including a furnace container 1 and a furnace lid 2 for closing the furnace container 1, the internal pressure of which is controllable; a heat insulating wall 6 provided within the pressure vessel 3 and opened to the furnace lid 2 to form a heating chamber 11 for storing a matter 7 to be treated in the inner part; a heat insulating lid 8 driven so as to open and close the opening part of the heat insulating wall 6; a heater 10 provided in the heating chamber 11 to heat the matter 7 to be treated; and a plurality of cooling fins 13 provided on the inner surface of the furnace lid 2 to cool a gas 18 in the pressure container 3.