Provided are: an antistatic agent which is capable of imparting excellent antistatic effect in a small amount and has sufficient persistence and wiping resistance; an antistatic agent composition; an antistatic resin composition; and a molded article.The antistatic agent comprises a polymer compound (E) having a structure in which a block polymer (C) and a polyhydric alcohol compound (D) are bound via an ester bond formed by a carboxyl group of the block polymer (C) and a hydroxyl group of the polyhydric alcohol compound (D), the block polymer (C) having a structure comprising carboxyl groups at both ends, in which structure a block constituted by a polyester (A) having carboxyl groups at both ends and a block constituted by a compound (B) having hydroxyl groups at both ends are repeatedly and alternately bound via ester bonds formed by the carboxyl and hydroxyl groups, and the polyhydric alcohol compound (D) comprising three or more hydroxyl groups.