PROBLEM TO BE SOLVED: To provide a heat evolution tool capable of achieving both of quick rise of heat evolution temperature and persistence of a heat evolution time.SOLUTION: A heat evolution tool 1 comprises: a flat heat evolution body 11 containing an oxidized metal, an electrolyte and water and a water retaining material 12 which is provided to contact the heat evolution body 11. In plan view of the heat evolution body 11, the water retaining material 12 is arranged to have two or more zones in which a water amount which can be held by the zone is different, and before start of heat evolution, the heat evolution body 11 has two or more zones in which a moisture content is different from each other. The water retaining material 12 is arranged so that a high basis weight zone having a relatively high basis weight and a low basis weight zone having a relatively low basis weight are formed, therefore a low moisture content area having a relatively low moisture content and a high moisture content area having a relatively high moisture content are formed on the heat evolution body 11.SELECTED DRAWING: Figure 1COPYRIGHT: (C)2017,JPO&INPIT【課題】発熱温度の速やかな立ち上がりと、発熱時間の持続性とが両立した発熱具を提供すること。【解決手段】発熱具1は、被酸化性金属、電解質及び水を含む扁平状の発熱体11と、該発熱体11と接するように配された保水材12とを備える。発熱体11を平面視したとき、保水材12が、保持可能な水分量が異なる2つ以上の区域を有するように配置され、発熱開始前において該発熱体11に含水率が異なる2以上の領域を備える。保水材12を、相対的に坪量の高い高坪量区域と、相対的に坪量の低い低坪量区域とが形成されるように配置し、それによって、相対的に含水率が低い低含水率領域と、相対的に含水率が高い高含水率領域とが発熱体11に形成されるようにすることが好適である。【選択図】図1
