A duplex-type product bag unloading apparatus including two downwardly opening and closing chucks and a chuck-moving mechanism for reciprocating the chucks between positions for receiving and discharging product bags. The relative positions of the two chucks are changed as they are moved from the receiving position to the discharging position by the chuck-moving mechanism, so that in the receiving position, the chucks are arranged in a single row in the bag width direction of the grasped product bags, and in the discharging position, the chucks are in a single row in the thickness direction of the grasped product bags. The chuck-moving mechanism is comprised of a pivot arm and a chuck-supporting frame rotatably mounted to the pivot arm, and the two chucks are rotatably mounted on both sides of the chuck-supporting frame. The chuck-supporting frame and the chucks rotate in synchronism with the pivotal motion of the pivot arm.