A resist underlayer film-forming composition which contains component (A), which is an isopolyacid, a heteropolyacid, a salt of an isopolyacid or heteropolyacid or a combination of these substances, and component (B), which is a polysiloxane, a poly(hafnium oxide), zirconium oxide or a combination of these substances, and wherein the component (A) is contained in an amount of 0.1-85% by mass based on the total amount of the component (A) and the component (B). The polysiloxane is a hydrolysis-condensation product of a hydrolyzable silane represented by R1 aR2 bSi(R3)4-(a+b), with the hydrolyzable silane represented by the formula wherein (a + b) is 0 being contained in an amount of 60-85% by mole relative to all hydrolyzable silanes contained therein. The poly(hafnium oxide) is a hydrolysis-condensation product of a hydrolyzable hafnium represented by Hf(R4)4. The zirconium oxide is a hydrolysis-condensation product of a hydrolyzable zirconium represented by Zr(R5)4 or ZrO(R6)2 or a combination of these substances.