Disclosed is a polyamide resin composition including 50% to 99% by mass of a polyamide (P) and 1% to 50% by mass of an acid-modified polyolefin (Q) satisfying the following requirements (1) to (3). (1) A melt flow rate (MFR) as measured at 230° C. under a load of 2.16 kg is 50 to 200 (g/10 min). (2) An acid modification amount is 0.1% to 2.0% by mass. (3) The acid-modified polyolefin (Q) includes a modified product (q1) of an elastomer including 10% to 95% by mole of an ethylene-derived skeleton unit, 0% to 80% by mole of a propylene-derived skeleton unit, and 3% to 40% by mole of a skeleton unit derived from an α-olefin having 4 to 8 carbon atoms (with a total amount of the ethylene-derived skeleton unit, the propylene-derived skeleton unit, and the skeleton unit derived from an α-olefin being 100% by mole), the elastomer being modified by maleic acid or an anhydride thereof.