PURPOSE: An aromatic polyester-amide resin excellent in heat resistance, mechanical strength, electrical insulation and moldability, containing specified structural units at a predetermined ratio.

CONSTITUTION: An aromatic polyester-amide resin consisting of structural units of formulas I WIV, bonded through an ester bond and/or an amide bond, wherein the molar ratio of the structural units is such that (units of formula I )/(units of formula II) is 9/1W1/9, and (units of formula III)/(units of formula IV) is 9/1W 1/9. Units of formulas I , II, III, and IV can be introduced by using monomers of terephthalic acid (derivative), isophthalic acid (derivative), 2,2-bis-(4'-hydroxylphenyl)propane and 2,2-(4'-hydroxy-4"-amino-diphenyl)propane.