We fabricated the 3-axis force sensor applicable to gait analysis. The 3-axis force sensor was fabricated by MEMS (Micro Electro Mechanical Systems) process. Its size was 8 mm x 8 mm * 5 mm and its weight was 0.6 g. The sensor was attached to the sole of the left foot. The sensor's size and weight were so small that it didn't interfere with human locomotion. Using this sensor, regional plantar 3-axis forces were measured during level walking on inside floor. From this measurement, peak values of forces experienced under third metatarsal were revealed; the peak value of vertical force was about 200N and that of antero-posterior shear force was about 90 N.