A dental cast scanning apparatus is comprised of a base; a single-tooth cast rotating device having a detachable and rotatable first cast-holding jig; a full-teeth cast rotating device having a detachable and rotatable second cast-holding jig; a scanning unit having a scanning probe, an elevator, and a slide rail mounted on the base, for slidable movement along the slide rail; and two swing drivers connected with the single-tooth and full-teeth cast rotating devices. Accordingly, the first and second cast-holding jigs can be driven to swing and rotate with respect to the scanning probe for a predetermined angle to cause efficient and effective scanning outcome.