There are disclosed a catalyst well suited for producing a styrenic polymer having a high degree of syndiotactic configuration which comprises a transition-metal compound such as pentamethylcyclopentadienyltrimethyltitanium and a coordination complex compound comprising an anion in which a plurality of radicals are bonded to a metal and a quaternary ammonium salt, the compound being exemplified by orthocyano-N-methylpyridinium tetra(pentafluorophenyl)borate, or comprises an alkylating agent such as triisobutylaluminum in addition to the above two compounds; and a process for producing a styrenic polymer having a high degree of syndiotactic configuration by polymerizing a styrenic monomer using the aforementioned catalyst. Consequently, a styrenic polymer having a high degree of syndiotactic configuration can be produced effectively without the use of an expensive aluminoxane required in a large amount if used.