A method of dividing an optical device wafer includes: a laser beam processing step of performing laser beam processing on the face side of an optical device wafer so as to form breakage starting points along streets; a protective plate bonding step of bonding the face side of the optical device wafer to a surface of a highly rigid protective plate with a bonding agent permitting peeling; a back side grinding step of grinding the back side of the optical device wafer so as to form the optical device wafer to a finished thickness of optical devices; a dicing tape adhering step of adhering the back-side surface of the optical device wafer to a dicing tape; a cut groove forming step of cutting the protective plate bonded to the optical device wafer along the streets so as to form cut grooves; and a wafer dividing step of exerting an external force on the optical device wafer through the protective plate, so as to break up the optical device wafer along the breakage starting points formed along the streets, thereby dividing the optical device wafer into the individual optical devices.