PURPOSE: To improve chamfering accuracy, to lessen the contamination of products and to enable chamfering with a series of stages by executing a stage for forming grooves before or after or simultaneously with a stage for obtaining color filters of prescribed sizes.

CONSTITUTION: A glass substrate 1 is fixed by using wax 55 for fixing on a stage 52 by positioning a color filter forming layer 50 side on an upper side and is placed on the stage of a dicing saw. Cutting lines 2b are aligned and the glass substrate 1 is cut to a product size by using a dicing blade 54b for cutting. Further, a dicing blade 54a for forming V-grooves is mounted at the dicing saw and the front end of the blade is aligned to the center of the cutting line and the substrate is cut down to the prescribed depth, by which the V- grooves are formed. The execution of the cutting stage of the substrate after the stage for forming the V-grooves is possible. A series of the operations are carried out by using the same dicing saw device and exchanging the blades.