The present disclosure provides a wafer grinding device comprising: a chuck table to suction the wafer thereon, a grinding wheel to grind the wafer by a predetermined thickness, wherein the grinding wheel includes a grinding body, and grinding teeth arranged along and on a bottom outer periphery of the grinding body, wherein the grinding teeth are segmented; and a cooling unit at least partially extending along a region between a departure point of the grinding teeth from the wafer during rotation of the teeth, and a re-encounter point of the teeth with the wafer during rotation of the teeth, wherein the region extends along rotation path of the grinding teeth.