The present invention provides a coating-type composition for forming an organic film containing: a polymer having a structure shown by the following general formula (1) as a partial structure; and an organic solvent, where in the formula (1), ring structures Ar1 and Ar2 represent a benzene ring or a naphthalene ring optionally having a substituent, and W1 represents an aryl group having 6 to 30 carbon atoms and optionally having a substituent. This provides a coating-type composition for forming an organic film that can form an organic film having high pattern-curving resistance and high dry-etching resistance, the composition being excellent in solvent solubility and having a low generation of defects.