This invention relates to a method for producing seaweed sheet containing a heat-treating step of treating a seaweed sheet, which is in a fixed sheet shape, by a superheated steam vapor for 1 second or more. In addition, This invention also relates to a heat processing machine for performing a heat-treating step to a sheet-like seaweed sheet, containing: a seaweed sheet placing part having an upper surface for placing seaweed sheet and an under surface opposite to the upper surface； a floating- suppressing part having an under surface provided so as to facing the upper surface of the seaweed sheet placing part, and the maximum distance between the upper surface of the seaweed sheet placing part and the under surface of the floating-suppressing part is 50 mm； a superheated steam nozzle for injecting a superheated steam to the seaweed sheet placed onthe seaweed sheet placing part； and a superheated steam producing device for generating a superheated steam and providing the superheated steam to the superheated steam nozzle.本發明關於一種燒海苔的製造方法，包含：將固定的薄片狀的海苔藉由過熱水蒸氣處理1秒以上之加熱處理步驟。此外，本發明關於一種用於薄片狀的海苔的加熱處理之加熱處理機，包含：海苔載置部，係具有用以載置海苔之上表面及與上表面為相反側之下表面；浮起防止部，係配置有與海苔載置部之上表面相對向的下表面，且海苔載置部之上表面與浮起防止部之下表面之最大間隔為50mm；過熱水蒸氣噴出口，係用以對載置於海苔載置部之海苔噴射過熱水蒸氣；以及過熱水蒸氣產生裝置，係用以產生過熱水蒸氣，並對過熱水蒸氣噴出口供給過熱水蒸氣。
