Abstract: A chair includes a seat support, a seat formed of two portions one of which is rigidly connected to the seat support, and a back rest also formed of two portions one of which is connected to another portion of the seat. The two seat portions are pivotally connected to each other and the two back portion are also pivotally connected to each other. The pivotable portion of the seat together with the back can swing from the sitting position of the chair to the backward-leaning rest position by means of a quadrangular linkage having four arms pivotally connected to each other. Two adjacent arms of the linkage are pivoted with respect to the rigid portion of the seat, about a pivoting connection near the horizontal axis of the pivotable portion of the seat.