The invention belongs to the field of mechanical equipment and relates to a gravity separation type automatic condensate water collector. The gravity separation type automatic condensate water collector comprises a primary steam-water separation tank, a secondary steam-water separation tank, a steam guide pipe, a condensate water guide pipe, a steam-water mixture inlet pipe and a condensate water discharge pipe. The primary steam-water separation tank is positioned below the secondary steam-water separation tank, and the steam guide pipe and the condensate water guide pipe are respectively arranged between the primary steam-water separation tank and the secondary steam-water separation tank. The steam-water mixture inlet pipe is mounted at one end, close to the top surface, of the lateral surface of the primary steam-water separation tank. The bottom end of the lateral surface of the secondary steam-water separation tank is provided with an outlet. One end of the condensate water discharge pipe is connected with an outlet of the secondary steam-water separation tank, and the other end of the condensate water discharge pipe is connected with a condensate water collection tank, the condensate water discharge pipe is provided with a U-shaped bend, and a sewage pipe is arranged at one end, close to the bottom surface, of the lateral surface of the primary steam-water separation tank. The gravity separation type automatic condensate water collector has the advantages of remarkable power saving effects, simple structure, convenience in use and promising application prospect.