The invention discloses a steel ball outputting device of a ball grinder. The steel ball outputting device comprises a material-drop protection conveying line, a waiting hopper, and an output port disposed in the ball grinder. One end of the material-drop protection conveying line is corresponding to the output port, and the other end of the material-drop protection conveying line is corresponding to the waiting hopper. An outlet of the waiting hopper is externally connected with an output. The steel ball outputting device is simple in structure, compact in connection, stable in output, high in efficiency, low in labor intensity and low in using cost.