Muscle has the most efficient actuation mechanism for known material. This research is for actuator with behavior of natural muscle concerning for characteristics like small size, enough force and linear movement. One of calling as artificial rubber muscle, DEA(Dielectric elastomer actuator) has overwhelming strains characteristics, efficiency and speed properties than natural muscle. Cylindrical roll type dielectric elastomer actuator is consisted of elastomer with electrode wrapped around to spring or another stiffener. Elastomer's spring constant and electrical force also increase as proportional to numbers of layers. We substitute spring constant to elongation-rate relation formula. And we concluded that 3~5 layers can produce enough strains of actuator. More layers can produce large forces and strains, but as numbers of layers increase, strain has become to saturated. Finally we graphed elongation rate vs numbers of layers and voltages using Matlab.