A syndiotactic propylene-based polymer composition which retains the inherent features of the conventional non-crosslinked or partially crosslinked olefin-based thermoplastic elastomer, and also has excellent abrasion resistance and flexibility. The syndiotactic propylene-based polymer composition comprises 1 to 40 parts by weight of the syndiotactic polypropylene (B), and 5 to 60 parts by weight of the syndiotactic structured propylene-α-olefin copolymer (C) comprising 95 to 65 mol % of a syndiotactic structured propylene component and 5 to 35 mol % of an α-olefin (except propylene) component having 2 to 20 carbon atoms, based on 100 parts by weight of the non-crosslinked or partially crosslinked olefin-based thermoplastic elastomer (A).