An automatic discharge connection device of a submersible pump is provided, which includes a coupling member coupled to a discharge port of the submersible pump and a feed pipe that feeds water discharged from the submersible pump. A sealing member is installed in an annular concave portion formed on an inner circumference of the coupling member in such a way as to move left and right. When the submersible pump is actuated, the sealing member moves toward the feed pipe and an end portion of the sealing member enters the feed pipe. Accordingly, a space between the coupling member and the feed pipe is sealed to thereby prevent water leakage between the coupling member and the feed pipe.