Adhesive composition and adhesive sheet

The invention provides an adhesive composition which has an excellent antistatic property, and is reduced in the variance in adhesivity to an object depending on the condition of the object or the peeling speed. The adhesive composition comprises the following components (A) to (C): (A) a (meth)acylic polymer produced by copolymerizing the following monomers (a1) to (a4) (provided that the total amount of the monomers (a1) to (a4) is 100 mass%): 10 to 70 mass% of a (meth)acrylic monomer having an alkylene oxide structure, (a2) 1 to 8 mass% of a monomer having a hydroxy group, (a3) 0.05 to 0.5 mass% of a monomer having one functional group selected from a carboxyl group, an amide group or an amino group, and (a4) 25 to 85 mass% of a (meth)acrylic acid alkyl ester; (B) a liquid ionic salt composed of an organic cation and an inorganic anion; and (C) an isocyanate crosslinking agent.