An electron-withdrawing group-containing metal compound (I) of an atom of the Group III to the Group XII or lanthanide series of the Periodic Table of the Elements, a catalyst component for addition polymerization composed of the compound (I), a catalyst for addition polymerization obtained by contacting the compound (I) with a specific compound (II) of metal of the Group III to the Group XIII or lanthanide series and optionally an organoaluminum compound (III), and a process for producing an addition polymer using the catalyst.