A wafer dividing apparatus for dividing a wafer along a plurality of crossing streets in the condition where the wafer is attached to the upper surface of a dicing tape supported to an annular frame and the strength of the wafer is reduced along the streets. The wafer dividing apparatus includes a frame holding unit for holding the annular frame, a wafer holding table having a holding surface for holding the wafer through the dicing tape supported to the annular frame held by the frame holding unit, a tape expanding unit for relatively moving the frame holding unit and the wafer holding table in a direction perpendicular to the holding surface of the wafer holding table to thereby expand the dicing tape, and a vibration generating unit for applying vibration to the holding surface of the wafer holding table.