Abstract: An automatic condensate draining device includes a housing which confines a condensate collecting chamber and having a base provided with a condensate discharge opening, and a condensate inlet opening in communication with the condensate collecting chamber. A valve seat unit has an axial through opening to intercommunicate the condensate collecting chamber and the condensate discharge opening. A poppet valve has a piston section in sliding contact with the inner surface of a lower portion of a tubular cover member, and a valve head to accordingly block the axial through opening of the valve seat unit. The piston section and the tubular cover member confine a volume variable chamber. Condensate and high pressure air enter the condensate collecting chamber via the condensate inlet opening and force the poppet valve upward so as to enable the valve head to block the condensate discharge opening.