Disposable foot warmer

A disposable foot warmer comprising a flexible inner bag which is made of materials having gas permeability and which contains a mixture of powders, main components of which are ferrous powders capable of generating heat when being oxidized with atmospheric oxygen and powders of pro-oxidants for the ferrous powders and an outer bag which is made of materials having no gas permeability and in which said inner bag has been vacuum packaged, said inner bag being capable of warming a foot as being applied to socks or stockings when the inner bag is generating heat, after the inner bag has been taken out of the outer bag, and after a releasing paper has been removed from the surface of a layer of an adhesive, said disposable foot warmer characterized in that the inner bag is shaped to have an area and a thickness which do not protrude out of the space between the plantar arch of a foot and an insole of shoes, so that the inner bag may be used as being applied to socks or stockings at their portion confronting the plantar arch of the foot, and that the inner bag has a front side made of materials having gas permeability and a back side made of materials which do not have gas permeability and which comprise a sheet of insulator and a layer of an adhesive applied to the sheet of insulator whereby to enable the inner bag to be applied to socks or stockings, so that heat emitted through the front side of the inner bag may warm air in the shoes and the insole of the shoes whereby to warm the whole foot, and so that heat conducted to the plantar arch through the back side of the inner bag may warm the sole of the foot without burning the plantar arch, whereby to enable the temperature to be raised in order to elongate the life of the disposable foot warmer.