To provide a method of manufacturing a warmer, which stably provides a warmer with high quality having both a heat giving function and a function other than giving heat.

The method of manufacturing a warmer is the method of manufacturing the warmer which includes the lamination body 4 constituted of a heat generation body 2, where an exothermic composition 8 containing metal to be oxidized contains an electrolyte aqueous solution, and of a liquid chemical containing sheet 3, where a liquid holding sheet 9 contains a liquid chemical containing a lipophilic medicine and the dissolving agent of the medicine. The method includes: a process for applying the liquid chemical to one surface of a belt shape liquid holding sheet 9' through the use of a contact type liquid chemical applying means 31, and then, obtaining a belt shape lamination body precursor 10' by superimposing the liquid holding sheet 9' on a belt shape exothermic composition 8', so as to allow one surface of the liquid holding sheet 9' to face the exothermic composition 8'; and a process for cutting the belt shape lamination body precursor 10' by prescribed length to obtain the sheets of lamination body precursors 10, and applying the electrolyte aqueous solution to the sheets of lamination body precursors 10 so as to obtain the lamination bodies 4.