A polyarylene sulfide resin composition characterized by comprising a polyarylene sulfide resin, and an olefinic copolymer comprising an α-olefin-derived structural unit and an α,β-unsaturated acid glycidyl ester-derived structural unit, wherein the olefinic copolymer content is at least 1.0 parts by mass and less than 5.0 parts by mass with respect to 100 parts by mass of the polyarylene sulfide resin, a melt viscosity of the polyarylene sulfide resin measured at 310° C. and a shear rate of 1216 sec−1 is at least 70 Pa·s and at most 300 Pa·s, and a flow length for a width of 20 mm and a thickness of 1 mm, at a cylinder temperature of 320° C., an injection pressure of 100 MPa and a mold temperature of 150° C., is at least 80 mm and at most 200 mm.