The invention discloses an automatic folding chair, comprising: a chair seat and a folding chair frame, wherein the folding chair frame comprises an automatic folding assembly, a rear supporting seat, and two front supporting seats symmetrically arranged on the left and the right; the automatic folding assembly comprises an adapter, a telescopic rod, and second connecting rods; the telescopic rod is further provided with a self-locking piece, and the self-locking piece has a locked state and an unlocked state; in the locked state, the self-locking piece can restrict the telescopic rod to expand and contract, which can improve the stability of the chair; in the unlocked state, the telescopic rod can actively expand and contract, which can simplify the user's operation and improve the convenience of use.