A wafer processing method for forming a modified layer within a wafer along planned dividing lines forms the modified layer within the wafer, positions a condensing point within the wafer or at a top surface of the wafer and applies a second laser beam while moving the condensing point, images reflected light, and determines a processed state of the wafer on the basis of an imaged image. The second laser beam is formed such that a sectional shape of the second laser beam in a plane perpendicular to a traveling direction of the second laser beam is not axisymmetric with respect to an axis along the planned dividing lines.