A substrate heat-treating apparatus includes a heat-treating plate, and support pins extending through the heat-treating plate to be vertically movable relative thereto. The support pins support each substrate at a lower surface thereof such that edges of the substrate are at a higher level than a central region of the substrate. This construction facilitates air flows into and out of a space between the lower surface of the substrate and the upper surface of the heat-treating plate when the substrate is vertically moved.