Pressure heating method and pressure heating apparatus

Disclosed are a pressure heating method and a pressure heating apparatus (1) which can prevent deformation of articles or deterioration of the quality of the articles due to supply of excessive pressure and heat. After performing pressurizing and heating processing of articles by supplying steam to a pressure vessel (2), the supply of steam is stopped and air is supplied to the pressure vessel to keep the internal pressure of the pressure vessel within the range not exceeding the maximum value of the internal pressure at the time of pressurizing and heating. A cooling water spray device (46,47) on a circulation pipe is operated along with a turbo blower (11) so as to condense it for gradual removal. After completing the removal of the steam, the articles are cooled by the operation of the cooling water jet unit (24,25,23). By avoiding an abrupt decrease in the pressure inside the pressure vessel through preventing an instant condensation of the whole steam, an excessive pre-load becomes unnecessary at the final stage of sterilization.