The present invention provides a material for an antireflective film characterized by high etching selectivity with respect to a resist, that is, which has a fast etching speed when compared to the resist, and in addition, can be removed without damage to a film which is to be processed. The present invention also provides a pattern formation method for forming an antireflective film layer on a substrate using this antireflective film-forming composition, and a pattern formation method that uses this antireflective film as a hard mask, and a pattern formation method that uses this antireflective film as a hard mask for processing the substrate. The present invention also provides an antireflective film-forming composition comprising an organic solvent, a cross linking agent, and a polymer comprising a light absorbing group obtained by hydrolyzing and condensing more than one type of silicon compound, a crosslinking group and a non-crosslinking group.