To provide an automatic stacking device which can directly and sequentially stack loads to be conveyed and supplied sequentially onto a moving vehicle and convey the stacked loads with the moving vehicle to a desired place.

A mounting horizontal frame part 4 capable of lifting along a guide mechanism 5 is provided on a machine body 3 provided with a conveyance opening part 2, a plurality of lock claw parts 7 are provided on this mounting horizontal frame part 4 for supporting and locking by rise with being hooked from below by a projection part 11 on an outer face of a load 1, the load 1 is lifted by the rise of the mounting horizontal frame part 4, and each of the lock claw parts 7 is lowered along the outer face of the load 1, resisting bias inward by lowering of the mounting horizontal frame part 4 to escape and rotate to an external force. When the load 1 on the load 1 is lifted by the rise of the lock claw part 7, between this lifted load 1 and the lower load 1, a supply opening part 10 for supplying another load 1 is provided on the side different from the conveyance opening part 2.