PROBLEM TO BE SOLVED: To provide heating bodies of various sizes and various shapes, showing good start-up of heating and favorably converted into a heating composition excellent in start-up of heating.SOLUTION: A manufacturing method of the heating body comprises the steps of: enclosing a heating precursor having a heating part containing an excess water-containing heating composition having an excess water value of 0.5-80 in an outer bag made of a packing material with a water-vapor permeability of 0.1-6.0 g/(m2×day) keeping the heating precursor in at least one environment chosen from a non-damaging natural environment and a controlled environment kept at a temperature of 1-80°C for a period ranging from 25 hours to 2 years and converting the heating precursor into the heating body having a water-containing heating composition showing an excess water value of 0 and a start-up temperature increase rate of &ge12°C/5 min. Here, the heating precursor essentially comprises an iron powder, a carbon component, a reaction accelerator and water. The heating body is also provided.COPYRIGHT: (C)2009,JPO&INPIT【課題】多種のサイズ、多種の形状を有し、立ち上がり発熱性に優れた発熱組成物への変換と立ち上がり発熱性のよい、発熱体を提供することである。【解決手段】鉄粉、炭素成分、反応促進剤、水を必須成分とし、余剰水値が0.5~80の含余剰水発熱組成物を含有する発熱部を備えた発熱前駆体を、透湿度が0.1~6.0g/(m2・day)である包材から構成される外袋に封入後、損傷を受けない自然環境下、及び、保持温度が1~80℃の制御環境下から選ばれた一種の環境下に保持し、該保持期間を、25時間~2年間とすることにより、余剰水値が0、且つ、立ち上り昇温速度が12℃/5分以上である含水発熱組成物を有する発熱体に変換する発熱体の製造方法及び発熱体である。【選択図】 図1
