To provide a chair made of corrugated paper, which can be quickly and easily assembled even in a disaster or the like while securing such strength that it is not destroyed even when used by an adult.

In the assembled chair made of the corrugated paper, in which a leg part Z has an integrated parallel cross structure 100 supporting a seat surface part X and a backrest part Y, and the seat surface part X and the backrest part Y are formed by covering the parallel cross structure 100 with an outer surface member 60, required strength is secured by turning a part where loads are to be applied to the integrated parallel cross structure, and it is easily assembled for a short period of time by using the same shape components, turning the parallel cross structure to a simple structure, and making it possible to crush it.