This heating tool (100) is provided with the following: a steam generator (10) which is obtained by laminating a water-absorbing sheet (102) that holds water and an exothermic layer (11) that contains an oxidizable metal, a carbon component, a water-absorbing polymer and water； and a bag (20) which houses the steam generator (10) and is at least partially air-permeable. The mass ratio of the water-absorbing sheet (102) relative to the water-absorbing polymer contained in the exothermic layer (11) is 0.9-15.本發明之溫熱器具(100)包括：水蒸氣產生體(10)，其係由含有被氧化性金屬、碳成分、吸水性聚合物及水之發熱層(11)與擔載水之吸水性片材(102)積層而成；以及袋體(20)，其於至少一部分具有透氣性，且收容水蒸氣產生體(10)；且吸水性片材(102)相對於發熱層(11)中所含之吸水性聚合物之質量比為0.9以上且15以下。
