The present invention provides a polyamide resin composition containing 1 to 10 part (s) by mass of swellable layered silicate and 0.01 to 0.3 part by mass of a phosphorus-containing compound having 3 or less phosphorus oxidation number to 100 parts by mass of polyamide resins, characterized in that, the polyamide resins comprise a polyamide resin A1 having relative viscosity of from 3.0 to 4.0 and a polyamide resin A2 having relative viscosity of from 1.5 to less than 3.0, that their mixing rate A1/A2 (in terms of ratio by mass) is from 98/2 to 5/95, and that tensile elongation at break of the polyamide resin composition is 3.0% or more. The polyamide resin composition has tenacity which has not been achieved in the conventional nano-composite and has excellent strength, rigidity and hot rigidity in spite of small content of inorganic filler and specific gravity.