A thermosetting composition comprising: (A) a (meth)acrylate compound having a viscosity at 25° C. of 1 to 300 mPa·s with which a substituted or unsubstituted aliphatic hydrocarbon group including 6 or more carbon atoms is ester-bonded; (B) spherical silica; and (C) a white pigment, and having a shear viscosity at 25° C. and 10 s−1 of 1 Pa·s or more and 500 Pa·s or less and a shear velocity at 25° C. and 100 s−1 of 0.3 Pa·s or more and 100 Pa·s or less.