Abstract: There is provided an interlocking supporting mechanism for supporting the seat and seat back of a chair, particularly an office chair. In the supporting mechanism a link system is utilized to interlock the seat with the seat back, so that the chair is capable of smoothly moving as a seated person moves.The front portion of a lever member is pivotally connected to the front portion of a frame member which is supported by a fixing member and which extends toward the front portion of the seat. The lever member is attached, with the aid of horizontal shafts on the right-hand and left-hand sides of the seat, to the lower portions of back supporting bars. A spring member is provided between the frame member and the lever member so that the lever member is rocked on the horizontal shafts. A member for receiving the seat includes a front seat-receiving member and a back seat-receiving member.