PURPOSE: To comfortably and equally support a user by arranging many elastic wires in parallel, connecting a member consisting of many bad conductors of heat, and forming a seat part and a back rest of a chair.

CONSTITUTION: An elastic member such as a piano wire 1, etc., is inserted through many bad conductors 2 of heat consisting of wood, and detained to an elastic wire-extending/fixing frame member 3. A prescribed number of pieces of planar structure forming bodies consisting of the piano wire 1 and the bad conductor 2 of heat are provided in parallel, and an end part of the piano wire 1 is detained to an indentation part 8 of the frame member. By a planar structure body 14 formed in such a way, a seat part 6 and a back rest 5 are constituted. In such a way, the seat part and the back rest coming into contact equally with the surface of the body of a user are formed.