Skin blood flow during exercise has been studied before, with measurements made using laser Doppler blood flowmeters; however, their use was limited to activities with minimal motion, such as riding bicycle ergometers, because conventional devices are large and their measurements easily altered by movements of the optical fiber, rendering them inappropriate for running. We have previously developed a micro integrated laser Doppler blood flowmeter using microelectromechanical systems (MEMS) technology. The micro blood flowmeter is wearable and can measure signal stably even while the wearer is moving. We monitored skin blood flow during running at velocities of 6 km/h, 8 km/h, and 10 km/h, and were successful in measuring a stable signal under these conditions. We found that at the forehead the skin blood flow increases and, in contrast, at the fingertip it initially decreases during running. We also found that the level of these increases and decreases correlated with the running velocity.