The present invention addresses the problem of providing a heating appliance that becomes hot during use and remains in a hot state for a long period of time. The present invention is a heating appliance including a heating agent and a packaging material enclosing the heating agent, wherein the packaging material is a flat bag-shaped material comprising a first surface and a second surface, and each of the first surface and second surface has a vent region and an air-impermeable region.以提供在使用時形成為高溫，而且高溫狀態持續長時間的發熱具作為課題。本發明係包含：發熱劑、及封入前述發熱劑的包材的發熱具，前述包材係由第一面及第二面所成之扁平袋狀，前述第一面及第二面係分別具有通氣區域、及非通氣區域。
