There are provided a method of forming a resist pattern that enables the resist pattern to be formed with good control of the pattern size, as well as a positive resist composition used in the method, and a layered product formed using the positive resist composition. In the above method a positive resist composition comprising a resin component (A), which contains a structural unit (a1) derived from a (meth)acrylate ester represented by a general formula (I) shown below, and displays increased alkali solubility under action of acid, and an acid generator component (B) that generates acid on exposure is applied to a substrate, a prebake is conducted, the resist composition is selectively exposed, post exposure baking (PEB) is conducted, alkali developing is then used to form a resist pattern, and the pattern size of the thus produced resist pattern is then narrowed by heat treatment.