Abstract: A semiaromatic polyamide resin composition comprising: (A) a polyamide copolymer in which a main constituent component unit is a polyamide formed of a recurring unit of a dicarboxylic acid component unit and a diamine component unit, at least not less than 45 mol % of said dicarboxylic acid component unit being a terephthalic acid component unit, and said diamine component unit comprising a straight-chain alkylenediamine component unit and/or an alkylenediamine component unit having a side-chain alkyl group; (B) an aliphatic polyamide containing, a unit derived from a lactam having 12 carbon atoms, a unit derived from an aminocarboxylic acid having 12 carbon atoms or a unit derived from a dodecanoic diacid and a diamine; and (C) a graft-modified product of a graft-modified ethylene/&agr;-olefin copolymer, a graft-modified product of an aromatic vinyl compound/conjugated diene copolymer, or a graft-modified product of a hydrogenated product of the aromatic vinyl compound/conjugated diene copolymer.