Disclosed herein is a wafer processing method including a wafer supporting step of mounting an adhesive film for die bonding on the back side of a wafer, attaching a dicing tape to the adhesive film, and supporting the peripheral portion of the dicing tape to an annular frame, wherein the wafer has already been divided into individual device chips along division lines formed on the front side or a break start point has already been formed inside the wafer along each division line, a protective film forming step of applying a water-soluble resin to the front side of the wafer and/or the peripheral portion of the adhesive film projecting from the outer circumference of the wafer, thereby forming a protective film from the water-soluble resin, and an adhesive film breaking step of expanding the dicing tape to thereby break the adhesive film along the individual device chips.