A long-fiber-reinforced resin composition including (A) a long-fiber-reinforced thermoplastic resin pellet including a thermoplastic resin, a modified polyolefin-based resin modified with an unsaturated carboxylic acid or its derivative and reinforcing fiber and satisfying (A-1) the melt index of the thermoplastic resin is 100-250 g/10 min, (A-2) the relaxation time λ of the thermoplastic resin is 0.1 (sec) or less, (A-3) the content of the reinforcing fiber is 40-70 wt %, and (A-4) the content of the modified polyolefin-based resin is 1-5 wt %; and (B) a polyolefin-based resin satisfying (B-1) the melt index of the polyolefin-based resin is 20-70 g/10 min, and (B-2) the relaxation time λ of the polyolefin-based resin is 0.23 (sec) or less; wherein the content of reinforcing fiber contained in (A) is 20-60 wt % relative to the total amount of the fiber-reinforced resin composition.