This paper reports a novel autonomous bio-microactuator powered by primary cultured cardiomyocytes and the control and evaluation of the contraction of skeletal muscle cell line C2C12 cells by means of electrical stimulation. To exploit contractions of cardiomyocytes, we fabricated a PDMS bulb-shaped dispenser and allowed cardiomyocytes to directly adhere to it. The displacement of the bulb-shaped dispenser by cardiomyocytes was larger than previously reported. Then, we employed electrical stimulation to control the contraction of muscle cells. The differentiated C2C12 cells (myotubes) were stimulated electrically, which was analyzed digitally. We succeeded in regulating contractions of C2C12 myotubes by electrical stimulations and manifested the relationship between contraction and the pulse frequency.