A polyamide composition containing a polyamide compound (A) and a transition metal compound (B), wherein the polyamide compound (A) contains: from 25 to 50 mol % of a diamine unit, which contains at least one diamine unit selected from the group consisting of an aromatic diamine unit represented by the following formula (I-1), an alicyclic diamine unit represented by the following formula (I-2) and a linear aliphatic diamine unit represented by the following formula (I-3), in an amount in total of 50% by mol or more; from 25 to 50 mol % of a dicarboxylic acid unit, which contains a linear aliphatic dicarboxylic acid unit represented by the following formula (II-1) and/or an aromatic dicarboxylic acid unit represented by the following formula (II-2), in an amount in total of 50% by mol or more; and from 0.1 to 50 mol % of a constitutional unit represented by the following formula (III): wherein m represents an integer of from 2 to 18, n represents from 2 to 18, Ar represents an arylene group, and R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.