To provide a heat generating body which nevertheless an excellent warming effect (for example, an effect for relaxation of a pain by a thermal stimulus) can be obtained, hardly provides a user with an unwell feeling due to a high temperature, is fit to curved surface parts such as the abdominal region and the waist and is able to comfortably warm a desired site with a good feeling for use over a long period of time. A heat generating body wherein three or more plural sectional exothermic parts are provided at intervals via a sectioned part which is a heat seal part, which is characterized in that the sectional exothermic parts have a heat generating composition capable of causing heat generation upon contact with oxygen in air and are at least constituted of three kinds of a low temperature sectional exothermic part, a middle temperature sectional exothermic part and a high temperature sectional exothermic part; that a maximum temperature of the high temperature sectional exothermic part is higher than a maximum temperature of the low temperature sectional exothermic part; that a maximum temperature of the middle temperature sectional exothermic part is laid between a maximum temperature of the high temperature sectional exothermic part and a maximum temperature of the low temperature sectional exothermic part; and that the middle temperature sectional exothermic part is constituted of plural sectional exothermic parts having a different maximum temperature.