To obtain the subject antistatic agent exhibiting electrostatic induction preventing effect in a polymer resin article even in a low-humidity environment and capable of preventing various troubles caused by electric charge by using a quaternary ammonium salt having a specific structure.

This antistatic agent is composed of a quaternary ammonium salt having a structure of formula I (R1 to R3 are each a 1-5C alkyl; R4 is a 1-2C alkyl). The compound of formula I can be produced e.g. by the alkylsulfonation reaction of dimethylaminoethanol with dimethyl sulfate or diethyl sulfate. The compound of formula II is preferable among the compounds of formula I. An antistatic coating agent and adhesive agent free from the lowering of electrostatic induction preventing effect even under a low-humidity low-temperature condition can be produced by adding a compound of formula I to a water-soluble polymer, an aqueous emulsion of a polymer or a polymer resin material soluble in a solvent such as ketone. The antistatic performance of a printing ink can be modified by adding the compound to a binder, etc., of a printing ink.