PROBLEM TO BE SOLVED: To provide a steam sterilizer not generating a problem of a sound or the like in vacuum drawing, capable of starting an operation surely, and transferring to a next operation, in a vacuum drawing step performed before a sterilization step.SOLUTION: Control means 34 of a steam sterilizer 1 controls vacuum drawing means 30 so that an operation is started when a value of pressure change in a chamber 11 exceeds a threshold.COPYRIGHT: (C)2016,JPO&INPIT【課題】滅菌工程の前に行う真空引き工程において、真空引きにおいて音などの問題が発生せず、確実に動作を開始し、次の動作へと移行できる蒸気滅菌器を提供する。【解決手段】蒸気滅菌器1の制御手段34は、チャンバー11内の圧力の変化の値が閾値を超えたときに作動を開始するよう真空引き手段30を制御する。【選択図】図1