Disclosed are a composition for 3D printer filaments satisfying requirements as a 3D printing material and a filament for a 3D printer manufactured using the same. A composition for 3D printer filaments including a polymer base containing atactic polypropylene having a weight average molecular weight of 50,000 to 1,000,000, a density of 0.8 to 0.9 g/ml, and isotacticity (Pentad I.I, mmmm) of 5 to 20%. The melting index (210° C., 2.16 kg) of the polymer base is 0.5-30 g/10 minutes, and a filament for a 3D printer manufactured using the same are provided.