Abstract: Provided is a polyamide resin having excellent heat shrinkability. A polyamide resin which contains three or more types of units, wherein the polyamide resin comprises (A) units derived from a lactam and/or an aminocarboxylic acid, and (B) units derived from an equimolar salt of a diamine and a dicarboxylic acid, wherein (B) the units derived from an equimolar salt of a diamine and a dicarboxylic acid comprise (B-1) units having no alicyclic structure and (B-2) units having an alicyclic structure.

Abstract: Provided is a polyoxamide resin which has excellent impact resistance and is characterized in that the polyoxamide resin is obtained from a diamine in which the diamine component has 10 to 18 carbons and in that the polyoxamide resin has a relative viscosity (?r) of 2.1 or greater as determined at 25° C. using 96% sulfuric acid as a solvent and a solution having a concentration of 1.0 g/dL, and also provided is an impact-resistant part comprising this resin. The polyoxamide resin has a higher molecular weight than a conventional polyoxamide resin, a large moldable temperature range as estimated from the difference between the melting point and the thermal decomposition temperature and therefore excellent molten moldability, and furthermore excellent impact resistance when compared to a conventional aliphatic polyoxamide resin without losing the low water absorbency, chemical resistance, hydrolysis resistance, high elasticity, and high strength seen with aliphatic straight-chain polyoxamide resins.