Provided is a superior heat generator with which unpleasant odors are controlled. Moreover, provided is the superior heat generator with which changes in fragrance are controlled. In addition, provided is the heat generator that is all the more superior in that even after storage, unpleasant odors are controlled and changes in fragrance are controlled. Provided is a method for controlling the generation of unpleasant odors and/or changes in fragrance with respect to the heat generator. The heat generator contains a heat generating composition comprising a metal ion sequestering agent, oxidizable metal particles, a water-soluble salt, and water, and at least the heat generating composition is stored in an air-permeable storage bag.提供一種業已抑制令人不愉快異味之更優異的發熱件。又，提供一種抑制香味改變之更優異的發熱件。又，提供一種在保存後仍可抑制令人不愉快異味且抑制香味改變之越發優異的發熱件。提供一種抑制發熱件產生令人不愉快異味及/或香味改變的方法。一種發熱件，係含有發熱性組成物且至少將前述發熱性組成物容納於具有透氣性之容納袋中而成者，該發熱性組成物含有金屬離子封鎖劑、可氧化性金屬粉、水溶性鹽類及水。
