PURPOSE: To develop the chair capable of making a quick recovery from fatigue by taking a comfortable posture for a while without changing a seat with respect to fatigue accumulated in the case of sitting on the chair for many hours on business or the like.

CONSTITUTION: In an office rotary chair, a seat receiver 1 of a rectangular box shape having both horizontal guide holes 2, 3 is installed under a seat 16, the left and the right supporters 10, 11 installed in the upper end part 19 of a leg part 18 so that the front part and the rear part become high and low, respectively and a bottom plate 12 for connecting them are combined and by moving a lever 13, the seat 16 and a back rest 17 are both inclined backward while advancing, and a comfortable seat state is realized.