Abstract: An automatic die exchanging device for injection molding machine, capable of automatically exchanging split dies on the machine. A mold exchanging base having at least two transfer passages is disposed at a lateral side of the molding machine. A split die composed of two die half parts locked to each other is placed on one of the transfer passages, and the base is moved to bring the vacant transfer passage to a lateral side of the die mounting portion of the molding machine. The die half parts of the die on the injection molding machine are unclamped from the platens and are locked to each other. This die is then transferred by a transfer means from the molding machine to the vacant transfer passage. Then, the base is moved to bring the transfer passage carrying the new die to the lateral side of the die mounting portion to transfer the new die to the molding machine. The die half parts of this new die are clamped to the platens and are unlocked from each other.