This paper reports on the sensor for traction force measurement of a smooth muscle cell during cell growth on a rigid substrate, specially designed for horizontal and vertical directional forces. For quantitative measurement, the cells are cultured only on the sensor pads using a cover chip. The length of the sensor is 1130μm. The size of the sensor pad is 125μm×15μ m×5μm (length×width× thickness). The gaps between the sensor pads are 3μm. We confirmed that the cells spread on the two sensor pads at least. We measured the traction forces of bovine aortic smooth muscle cells (BAOSMCs, CAB35405) using the proposed sensor. When the three cells spread on the pads, the measured traction forces in x and z direction increased 30nN and 20nN for 8 min, respectively.