A wafer processing apparatus including a supporting unit having a frame fixing section fixing the frame, and a wafer table having a front side and a rear side, the front side including a supporting face supporting the wafer and a transparent plate, a liquid layer forming unit including a nozzle section and forming a layer of a liquid on the supporting face of the wafer table, an imaging unit including an imaging camera positioned adjacent to the rear side of the wafer table and opposite to the supporting face on the front side of the wafer table and an air blowing nozzle blowing air to a region between the wafer table and the adhesive sheet.