Abstract: Warming footwear, which has a heat exchanging system 1 built in an inshoe 2 from a shin portion d over an instep portion c and a toe portion b to a calf portion a. The system 1 is composed of a ribbed plate 11, of an elastic foil 12 and of two nonreturn valves 13, 14, which valves are inserted in two conduits, which are limited by the plate 11, by its ribs and by the foil 12, which is fastened to said ribs and functions as bellows when the foot moves and across which a liquid in the conduits receives and renders heat. Alternatively, in the instep portion c a sunlight collector 4 is performed.