PURPOSE: To enable heating simply by a method wherein a bag-shaped housing part is formed on the surface side of a seat cover covering a seat part holstering and a back rest part upholstering composing a foldable chair to house and a carrying disposable pocket heater is housed free to load or unload.

CONSTITUTION: A foldable chair 1 is provided with a seat part upholstering 2 and a back rest upholstering 3 and both the pieces of upholstering 2 and 3 are covered with a seat part upholstering cover 4 and a back rest part upholstering cover 5 respectively. The seat part upholstering cover 4 and the back rest part upholstering cover 5 have bag-shaped housing parts 6 and 7 on the surface sides thereof respectively, openings thereof are made free to open or close with planar fasteners 8 and 9 and carrying disposable pocket heaters 10 are housed into the housing parts 6 and 7. A user takes out and opens the pocket heaters 10 as required and shakes them thoroughly to be housed into the bag-shaped housing parts 6 and 7. This enables heating simply even under a prolonged seating outdoors and at a place where a heating equipment is not arranged.