To obtain a polyamide copolymer improved in processability, compatibility and elastomeric property and useful as an adhesive, etc., by using a specific diamine component and a specific aromatic dicarboxylic acid component.

This polyamide copolymer comprises 0.1-100 mol.% repeating structural unit represented by formula I [Ar is a bifunctional aromatic group; R is ≤10C bifunctional aliphatic group; (x) and (y) represent each content ratio of Ar-containing diamine and R-containing diamine and (x)+(y)=1; (n) is a repeating structural unit and 50≥(n)≥1] and 0-99.9 mol.% repeating structural unit represented by formula II [Ar1 is same as Ar; (a) and (b) represent each content ratio of Ar1 and Ar-containing diamine and R-containing diamine and (a)+(b)=1] which are irregularly bonded. Furthermore, the objective copolymer is obtained by using, e.g. a diamine component containing at least 0.1 wt.% diamine of an aliphatic polyether obtained by esterifying both ends thereof with an aminobenzoic acid and an aromatic dicarboxylic acid component containing at least 0.1% monomer of an aromatic dicarboxylic acid having phenolic OH group.