To provide a sterilizer that can deal with closing failure of a steam supply valve with a simple structure and control and suppress food wastes by preventing overheating and quality deterioration of food.SOLUTION: A sterilizer is equipped with a processing tank 3 to house an article to be processed 2 and store water, circulation means 10 to circulate the water stored in the processing tank 3 using a circulation line 15, and steam supply means 11 to supply steam to a heat exchanger 9 installed on the circulation line 15 and heat the circulation water. The steam supply means 11 includes a steam supply shutoff valve 31 to switch on and off steam supply and a steam supply valve 32 of which the opening is adjustable in series on a steam supply line 30 to the heat exchanger 9. In a sterilizing step, the opening of the steam supply valve 32 is adjusted while the steam supply shutoff valve 31 is open. When the temperature in the processing tank 3 reaches a steam supply shutoff temperature or higher, the steam supply shutoff valve 31 is closed. When the temperature in the processing tank 3 reaches the steam supply shutoff temperature or lower afterward, the steam supply shutoff valve 31 is opened.SELECTED DRAWING: Figure 1【課題】簡易な構成および制御で、給蒸弁の閉鎖不良に対応して、食品の過加熱や品質劣化を防止することで、食品の廃棄を抑制できる殺菌装置を提供する。【解決手段】被処理物２が収容されると共に水が貯留される処理槽３と、この処理槽３内の貯留水を循環路１５を介して循環させる循環手段１０と、循環路１５に設けた熱交換器９に蒸気を供給して循環水を加熱する給蒸手段１１とを備える。給蒸手段１１は、熱交換器９への給蒸路３０に、給蒸の有無をオンオフで切り替える給蒸遮断弁３１と、開度調整可能な給蒸弁３２とを直列に備える。殺菌工程では、給蒸遮断弁３１を開けた状態で、給蒸弁３２の開度を調整するが、処理槽３内の温度が給蒸遮断温度以上になると、給蒸遮断弁３１を閉じる一方、その後、処理槽３内の温度が給蒸再開温度以下になると、給蒸遮断弁３１を開ける。【選択図】図１
