This invention provides a radiation-sensitive resin composition comprising (A) an alkali-soluble resin having unsaturated groups which is obtained by reacting 100 parts by weight of a copolymer comprising 1 to 40 wt% of constituent units derived from a radical-polymerizable compound (a) having a carboxyl group, 1 to 50 wt% of constituent units having phenolic hydroxyl groups which are derived from a radical-polymerizable compound (b-1) having a phenolic hydroxyl group or a radical-polymerizable compound (b-2) having a functional group which can be converted into phenolic hydroxyl after the formation of the copolymer, and the balance of constituent units derived from other radical-polymerizable compound (c) with 0.1 to 20 parts by weight of a radical-polymerizable compound (d) having an epoxy group, (B) a compound having at least one ethylenically unsaturated double bond, and (C) a polymerization initiator for radiation-initiated radical polymerization. The composition is characterized by forming a radiation-sensitive resin coating film having a thickness larger than the height of a deposit and high resolution.