A scaffold of a transparent film with micro pattern markers has been designed to measure the contractile force of myotube under electric stimulation in vitro. The scaffold is made of a thin film (thickness 0.006 mm), of which the back side has arrangement of polydimethylsiloxane micro-protrusions (0.004 mm diameter, 0.002 mm height, 0.003 mm interval) made by the photolithography technique. C2C12 (mouse myoblast) was seeded on the film at the counter surface to the protrusions at the density of 50000 cells/cm2. The cells were cultured on the scaffold for 12 days in the medium containing 10% FBS (fetal bovine serum) and 1% penicillin/ streptomycin at 310 K with 5% of CO2 content. The electric pulses (amplitude of 30 V (0.06 A) ; pulse cycle of 1 s; pulse width of 1 ms) were applied between electrodes of the titanium wire dipped in the medium. The contraction of myotubes is able to be observed through the transparent scaffold at the microscope. The contractile force of myotube at the electric stimulation estimated by the deformation of the film was 10-4 N. The designed scaffold has a potential for the measurement of the local contractile force of the myotube microscopically in vitro.