Disclosed is a polypropylene-based resin composition including:from 60 to 94.9% by weight of propylene-ethylene block copolymer (A) which has a propylene homopolymer portion (A1) in a content of from 60 to 75% by weight and a propylene-ethylene random copolymer portion (A2) in a content of from 25 to 40% by weight or a mixture of the propylene-ethylene block copolymer (A) and 20% by weight or less of propylene homopolymer,from 0.1 to 15% by weight of resin (B) which has a melt tension of 0.03 N or more, a swelling ratio of 1.5 or more and a relaxation time of 5 seconds or more; andfrom 5 to 25% by weight of inorganic filler (C).