<p>A radiation-sensitive resin composition comprising: a resin having acid-dissociable groups which is insoluble or sparingly soluble in alkalis, has a specific structure that makes the resin alkali-soluble by the action of an acid, and is obtained by living radical polymerization; and a radiation-sensitive acid generator, wherein the ratio of the weight-average molecular weight to the number-average molecular weight of the resin having acid-dissociable groups [(weight-average molecular weight)/(number-average molecular weight)] is 1.5 or lower.</p>
