Recently, the microrobots powered by biological muscle actuators were proposed. Among the biological muscle actuators, frog muscle is well known as a good muscle actuator and has a large displacement, actuation forces and piezoelectric properties. Therefore, for the application of the biomimetic microrobot, this paper reports the electromechanical properties of frog muscle. First of all, the experimental setup has been established for measuring generative force of the frog muscle. Through the various electrical stimulating inputs to the frog muscle, we measured the contractile force of the frog muscle. From the measuring results, we found that the actuating contractile force responses of the frog muscle are determined by the amplitude, frequency, duty ratio, and wave form of the stimulation signal. This study will be beneficial for the development of the microrobot actuated by frog muscle.