The invention relates to a device for automatically discharging and conveying steel balls. The device comprises a vertical mounting plate vertically and fixedly mounted on a bottom plate; a feed mechanism, a material-separating mechanism, a blanking mechanism and a discharging mechanism which are sequentially mounted on the vertical mounting plate from top to bottom; and a fiber-optical probe is arranged on a steel ball channel of the material-separating mechanism. Conveyed steel balls are input from the feed mechanism, divided into the number of predetermined batches through the material-separating mechanism and then output through the blanking mechanism and the discharging mechanism, and after the number of each batch of the steel balls is detected by the fiber-optical probe, the conveying of the material-separating mechanism to the blanking mechanism is controlled by a control system. The invention has simple structure and high conveying efficiency and can convey various kinds of steel balls.