An embodiment of the present invention provides a surface plate provided at a wafer double-side grinding device for grinding a wafer. The surface plate includes a plurality of first surface plate grooves formed in a first direction, and a plurality of second surface plate grooves formed in a second direction different from the first direction. The first surface plate grooves and the second surface plate grooves have first and second surface plate groove portions arranged therein, the first and second surface plate groove portions having steps formed in a direction toward the center or an outer periphery of a lower surface plate.