The present invention relates to a polymer blend composition comprising a dielectric elastomer, an actuator film manufactured using the same, and an actuator comprising the film. The polymer blend composition according to the present invention comprises a block copolymer having excellent compatibility with the dielectric elastomer and excellent dielectric properties, and thus displacement values suitable for the purpose can be obtained by a simple method of adjusting a composition of the polymer blend. Moreover, the film manufactured using the same has high dielectric constant, low dielectric loss and high electromechanical displacement, and thus the film exhibits excellent dielectric properties when it is applied in a dielectric layer for an actuator.