PURPOSE: To completely and quickly wipe off an adhesive adhering to an undercoating after peeling of a tape while being observed with eyes, by using a colored adhesive layer-bearing parting masking tape as a masking means.

CONSTITUTION: The (A) color-based paint of desired two-tone color (B)/(A) is applied on a selected area of an interlayer coating and baked to form a (A) color-based coating 4. Then, a colored adhesive layer-bearing masking tape is stuck 9 on the needed area of the (A) color-based coating 4 for masking so as to form a parting line 5 and not to paint the desired part of the (A) color-based coating 4 with a (B) color paint. Under this condition, a (B) color- based paint is applied and baked to form a (B) color-based coating. After that, the tape is peeled and the remaining adhesive adhering to the undercoating is wiped off with a thinner, etc. while being observed with eyes to complete the two-tone coating.