This review article mainly describes our recent results on the supported-type metallocene catalysts. A variety of catalysts were prepared and used as catalysts for olefin polymerizations. From the detailed analyses of catalysts and of resulting polymers, the effects of carriers on the catalyst performance were discussed. Brief results are also reported on a novel MgCl₂-supported Ziegler-Natta catalyst, which may be of use to develop a post metallocene catalyst.