The present invention provides a novel catalyst composition comprising a metallocene complex, and a novel producing method for various polymer compounds. Preferably, the invention provides a novel polymer compound, and a producing method thereof. Specifically, the invention provides a polymerization catalyst composition, comprising: (1) a metallocene complex represented by the general formula (I), including: a central metal M which is a group III metal atom or a lanthanoid metal atom; a ligand Cp* bound to the central metal and including a substituted or unsubstituted cyclopentadienyl derivative; monoanionic ligands Q1 and Q2; and w neutral Lewis base L; and (2) an ionic compound composed of a non-ligand anion and a cation: where w represents an integer of 0 to 3.