To develop an opacifying composition for coating excellent in optically opacifying properties and sealing properties at a coated spot, excellent in designing the coated surface, giving easy confirmation of the presence or absence of the coated material at the coated spot, and for aiming at improving corresponding ability to naked eye and optical inspection processes during assembly of a product and the like, and, at the same time, a highly functional opacifying composition for coating having more excellent heat resistance and coating workability than those of conventional opacifying compositions.

A composition comprising a dispersion medium and an inorganic pigment dispersed therein is brought to be the opacifying composition for coating, wherein the dispersion medium includes 98-80 pts.mass polybutene having 1,000-2,500 number average molecular weight and 2-20 pts.mass polyethylene having 0.916-0.930 g/cm3 density and 4 MFR (the total thereof being 100 pts.mass), and a 0.1-10 pts.mass inorganic pigment is dispersed in the dispersion medium.