An automatic circulation device of warm water includes a boiler respectively formed with a feed port and a discharging port at the upper side and the lower side thereof, an electric heater horizontally installed at the inner lower side of the boiler without contacting the inner lower side and supplying heat to the interior of the boiler, a water tank connected to the feed port of the boiler by means of a feed pipe and feeding the cool water to the boiler, a heat exchanging section connected to the discharging port of the boiler by means of a discharging pipe and to the water tank by means of a circulation pipe, and transferring heat to the exterior, and a feed valve and a discharging valve respectively installed to the feed pipe and the discharging pipe, and automatically opened and closed by vapor pressure in the boiler. The automatic circulation device continuously produces and circulates the warm water regardless of the distance and height without using a separate pump.