Foot warming heating element and method of manufacturing foot warming heating element

A heat-generating body for warming a foot which comprises a container bag formed of a base material and a covering material and said container bag being charged with a formed heat-generating composition which can cause a heat generating reaction in the presence of air, the container bag being air permeable on at least at a part thereof;

• the formed heat-generating composition has a water mobility value of from 6 to 20, and the heat-generating composition contains, as essential components, from 1.0 to 50 parts by weight of a carbon component, from 0.1 to 10 parts by weight of a reaction accelerator and from 20 to 60 parts by weight of water, per 100 parts by weight of iron powder as a heat-generating substance generating heat upon reaction with oxygen, to which at least one kind selected from the group consisting of a water retaining agent, a water absorbing polymer, a pH adjusting agent, a hydrogen generation suppressing agent, a syneresis preventing stabilizer, a surface active agent, a defoaming agent, a hydrophobic polymer compound, a pyroelectric substance, a far infrared ray radiating substance, a negative ion generating substance, an aggregate, a fibrous material, a thickener, a binder, a fertilizer component and a heat-generating assistant is mixed depending on necessity.