A primer comprising at least one selected from the group consisting of dyes and pigments, and, optionally, at least one selected from the group consisting of an organosilicon compound represented by Formula (I): ##STR1## wherein R.sup.1 represents a monovalent hydrocarbon group; R.sup.2 represents a substituted or unsubstituted monovalent hydrocarbon group; R.sup.3 represents X-- or X-R.sup.4 --, where X represents a monovalent hydrocarbon group containing an epoxy group, etc., and R.sup.4 represents a saturated divalent hydrocarbon group; and n is an integer of 0 to 2,and a partial hydrolyzate thereof. This primer can import a good adhesion to so-called hardly adherable materials such as polyolefin plastics.