PROBLEM TO BE SOLVED: To provide a method for efficiently heating fluid in a short time.SOLUTION: There are provided: a manufacturing method for warming fluid which is a method for manufacturing warming fluid by irradiating a heated body comprising carbonaceous matter present in fluid with microwaves, the carbonaceous matter being characteristically oxidation proof carbonaceous matter or flame-retardant treated carbonaceous matter obtained by thermally-treating a mixture of a flame-retardant agent and carbonaceous matter； a sterilization method, an extracting method, and electric power generation method using warming fluid； and a microwave irradiation material which is characteristically flame retardant agent treated carbonaceous matter and oxidation proof carbonaceous matter obtained by thermally treating a mixture of a flame retardant agent containing phosphorus, boron or metal atom and carbonaceous matter.【課題】効率良く短時間で流体を加熱する方法を提供すること。【解決手段】炭素質物を流体中に存在させてなる被加熱体にマイクロ波を照射して加温流体を製造する方法であって、該炭素質物が、耐酸化性炭素質物、又は、難燃化剤と炭素源物質との混合物を熱処理して得られた難燃化剤処理炭素質物であることを特徴とする加温流体の製造方法、該加温流体を用いた殺菌方法、抽出方法、発電方法、及び、リン、ホウ素又は金属原子を含有する難燃化剤と炭素源物質との混合物を熱処理して得られた難燃化剤処理炭素質物であって耐酸化性炭素質物であることを特徴とするマイクロ波照射材料。【選択図】なし
