Provided is a disposable body warmer with which the dispersion, from an outer package, of moisture included in a heat-generating composition is inhibited, and with which an excellent heat-generation duration can be maintained, even if kept in an unused state for an extended period of time. In this disposable body warmer (1), a heat-generating composition (2), which generates heat as a result of coming into contact with air, is enclosed in air-permeable inner packages (3), and the inner packages (3) are accommodated in an airtight outer package (4). The outer package (4) is provided with at least 3 accommodation portions (42) which are capable of accommodating the inner packages (3), and which are separated from each other. The inner packages (3) are each provided with at least 2 enclosure portions (32) which are capable of enclosing the heat-generating composition (2), and which are separated from each other. The inner packages (3), each of which being in a state of having been folded at least once such that at least one of the enclosure portions thereof is on top of another of the enclosure portions thereof, are accommodated in the accommodation portions (42).L'invention concerne un dispositif de chauffage jetable pour le corps qui inhibe la dispersion, à partir d'un emballage externe, d'humidité incluse dans une composition générant de la chaleur et qui permet de maintenir une excellente durée de génération de chaleur, même s'il est conservé dans un état non utilisé pendant un laps de temps prolongé. Dans ce dispositif de chauffage jetable pour le corps (1), une composition générant de la chaleur (2), qui génère de la chaleur suite à son contact avec l'air, est renfermée dans des emballages internes perméables à l'air (3) et les emballages internes (3) sont logés dans un emballage externe étanche à l'air (4). L'emballage externe (4) est muni d'au moins 3 portions de logement (42) qui peuvent loger les emballages internes (3) et qui sont séparées les unes des autre
