Patent ID: 7540878

Claim:
A thermotherapy device comprising a plurality of heat generation portions disposed on a flexible body having a form of a band, the plurality of the heat generation portions each comprising a base sheet and an oxygen permeable sheet forming the flexible body, an accommodation portion formed between the base sheet and the oxygen permeable sheet and having a form of a bag, and a exothermic composition that generates heat when oxidized filled in the accommodation portion, wherein the filling ratio R of the exothermic composition in the accommodation portion satisfies the expression below and is less than 0.7: R≦ −0.016 S +0.94 wherein S is the planar area of the accommodation portion of the exothermic composition expressed in cm 2 , and R is defined by the following expression: R=the ratio of the mass of the exothermic composition in the accommodation portion to the maximum mass of the exothermic composition that can be filled in the accommodation portion; and the heating value of the exothermic composition in the accommodation portion is not less than 0.26 kcal/cm 2 per planar area of the accommodation portion.