PROBLEM TO BE SOLVED: To provide a sterilization drying method by a soft hydrothermal process having high sterilization performance, capable of performing a sterilization treatment in a short time, without requiring separately a drying step.SOLUTION: A sterilization drying method by a soft hydrothermal process has a sterilization drying step (step ST13) in which steam generated in a boiler 11 which is a steam generation part is circulated via a pressure vessel 13 which is a treatment chamber storing a treatment object which is a sterilization object, in the state of highly saturated steam having a steam saturation degree not lower than 100%, to thereby perform simultaneously sterilization and drying of the treatment object.SELECTED DRAWING: Figure 4COPYRIGHT: (C)2017,JPO&INPIT【課題】滅菌性能が高く、乾燥工程を別途必要とすることなく短時間で滅菌処理を行うことのできるソフト水熱プロセスによる滅菌乾燥方法を提案すること。【解決手段】ソフト水熱プロセスによる滅菌乾燥方法では、蒸気発生部であるボイラー11で発生させた水蒸気を、蒸気飽和度が100%を下回らない高飽和水蒸気の状態で、滅菌対象の被処理物を入れた処理室である圧力容器13を経由して流通させ、被処理物の滅菌および乾燥を同時に行う滅菌乾燥工程(ステップST13)を有している。【選択図】図4