This invention relates to an aromatic vinyl compound-conjugated diene compound copolymer capable of giving excellent wear resistance and resistance to wet skid to a tire, and more particularly to an aromatic vinyl compound-conjugated diene compound copolymer obtained by an addition polymerization of an aromatic vinyl compound and a conjugated diene compound in the presence of a polymerization catalyst composition comprising at least one specified metallocene complex selected from the group consisting of a metallocene complex represented by the following general formula (I): (wherein M is a lanthanoid element, scandium or yttrium, and CpR is independently a non-substituted or substituted indenyl, and Ra to Rf are independently an alkyl group having a carbon number of 1-3 or a hydrogen atom, and L is a neutral Lewis base, and w is an integer of 0-3) and so on, wherein a content of cis-1,4 bond in a conjugated diene compound portion is not less than 80%.