A heating implement wherein: (A) said heating implement contains 40 to 80 mass parts of water per 100 mass parts of an oxidizable metal (B) said heating implement contains 0.3 to 20 mass parts of a water-retention agent per 100 mass parts of the oxidizable metal (C) a heat-generating layer (121A) contains 8 to 45 mass parts of water per 100 mass parts of the oxidizable metal and (D) the amount of water retained in a water-retention sheet (121C) is 15-30 mass% of the maximum water-absorption capacity of said water-retention sheet.本發明之溫熱器具係(A)溫熱器具中所含之水分量相對於被氧化性金屬100質量份為40質量份以上且80質量份以下,(B)保水劑之含量相對於被氧化性金屬100質量份為0.3質量份以上且20質量份以下,(C)發熱層(121A)中所含之水分量相對於上述被氧化性金屬100質量份為8質量份以上且45質量份以下,(D)保水片材(121C)中所含之水分量為保水片材之最大吸水量的15~30質量%。120‧‧‧發熱體121‧‧‧發熱部121A‧‧‧發熱層121B‧‧‧片材121C‧‧‧保水片材122‧‧‧第1袋體122A‧‧‧第1片材122B‧‧‧第2片材
