A method of forming a fine pattern, including: a phase separation step in which a layer containing a block copolymer having a plurality of blocks bonded is formed on a substrate, and then the layer is heated for phase separation of the layer; a decomposition step in which at least a portion of a phase of at least one block of the plurality of blocks constituting the block copolymer is decomposed; a selective removal step in which the layer is immersed in a developing solution to selectively remove a phase containing decomposed blocks to form a nano structure; and an etching step in which the substrate is subjected to etching by using the nano structure as a mask; and a main component of the developing solution is an organic solvent having an SP value of 7.5 to 11.5 (cal/cm3)1/2, and having vapor pressure of less than 2.1 kPa at 25° C., or is benzene that may be substituted by an alkyl group, an alkoxy group, or a halogen atom, and the developing solution further contains metal alkoxide.