To provide a folding chair which is small and can be carried in a bag, and is just put between the legs and sat and shows almost the same figure of sitting up with first toes crossing each other as usual, and prevents a local pain in the bottom, keeps the sitting height almost the same as usual, and prevents a cushion from damage.

The almost central width of a belt which is set longitudinally long on the folding chair for sitting up when the chair stands with the shorter side in front is made longer than the width between a pair of hipbones and shorter than the width between the heels which are facing each other during sitting up, and there is a method for securing the central height of the belt according to the length set constant or variable between the X-shaped supporting legs when they make a maximum distance.