There is disclosed a resist lower-layer composition configured to be used by a multi-layer resist method used in lithography to form a layer lower than a photoresist layer acting as a resist upper layer film, wherein the resist lower-layer composition becomes insoluble or poorly-soluble in an alkaline developer after formation of the lower layer, and wherein the resist lower-layer composition comprises, at least, a thermal acid generator for generating an acid represented by the general formula (1) by heating at a temperature of 100° C. or higher. RCOO—CH2CF2SO3−H+  (1) There can be provided a resist lower-layer composition in a multi-layer resist method (particularly, a two-layer resist method and a three-layer resist method), which composition is used to form a layer lower than a photoresist layer acting as a resist upper layer film, which composition becomes insoluble or poorly-soluble in an alkaline developer after formation of the lower layer, and which composition is capable of forming a resist lower layer film, intermediate-layered film, and the like having a higher anti-poisoning effect and exhibiting a lower load to the environment.