Adjusting device for adjusting inclination angle of chair back

The utility model discloses an adjusting device for adjusting the inclination angle of a chair back, which comprises a fixed seat and a movable seat, the fixed seat comprises a fixed end and an adjusting end, the fixed end is connected with a supporting leg of a chair, and the adjusting end is sleeved on the end part of a rotating shaft for rotating the chair back; the rotating seat is fixed at the end part of the rotating shaft, a rotating groove is formed in the rotating seat, and a fixing hole is formed in the rotating groove; one end of the clamping shaft is nested in the fixed end and clamped in the rotating groove, and the other end of the clamping shaft extends outwards and is provided with a clamping structure; and the knob switch comprises a rotating piece and a rotating shaft, the rotating shaft is nested in the rotating seat, and a cam structure is arranged on the outer side of the shaft wall. Through simple rotation of the knob switch, the clamping shaft can be switched between a fixed state and a