A novel device for automatically supplying golf balls. A stopper, a golf ball lifting part, an inclined guide part and an inclined lifting part disposed inside a main body cooperate with each other to automatically lift a golf ball from a rear portion of the main body by placing the golf ball on a lifting tee so that a golfer can hit the ball using a driver. An iron shot hitting part is further provided at one side of the main body so that the golfer can practice driver shots and iron shots concurrently and conveniently at the same time. The lifting tee is inclined to the left in order to supply a ball seated on the inclined lifting part to the iron shot hitting part. The iron shot hitting part has a plurality of detection recesses with which a golfer or a beginner can correct his/her posture.