PROBLEM TO BE SOLVED: To provide a production method and a manufacturing apparatus of a safe bivalve such as an oyster having a small risk of causing norovirus food poisoning while inhibiting lowering of deliciousness/texture/appearance of the oyster.SOLUTION: A shucked shellfish such as an oyster is steamed by using steam at a temperature of 100°C or higher and a pressure of 1 kgf/cm2G or less. A manufacturing apparatus thereof is also provided.COPYRIGHT: (C)2014,JPO&INPIT【課題】ノロウイルス食中毒を起こす危険性の低い安全な牡蠣などの二枚貝の旨味・食感・外観などの低下を抑制する生産方法および製造装置を提供する。【解決手段】牡蠣などの剥身を、100℃以上の温度かつ1kgf/cm2G以下の圧力の蒸気を用いてを蒸す。またその製造装置を提供する。【選択図】図2