An optical device wafer has a plurality of optical devices formed on a front side and a plurality of crossing division lines for partitioning the optical devices. Each optical device has electrodes formed on the front side. A processing method includes: forming a groove on the front side of the wafer along each division line, the groove having a depth reaching a finished thickness; of forming a nonconductive reflective film on the front side of the wafer to thereby form the reflective film on at least the side surfaces of the groove; removing the reflective film formed on the electrodes to thereby expose the electrodes; and grinding a back side of the wafer to thereby reduce the thickness to the finished thickness until the groove is exposed to the back side of the wafer to divide the wafer into individual optical device chips.