In this study, we observed muscle activity of common digital extensor muscle and flexer digitorum superficialis muscle in forearm with the multi-channel electromyography (EMG) measurement system using conductive fabric for research the mechanism of finger tremor. We compared up and down motion of laser pointer affixed to middle finger to muscle activity of common digital extensor muscle and flexor digitorum superficialis muscle. As a result, common digital extensor muscle move a few msec earlier if middle finger moved upward, and flexor digitorum superficialis muscle move a few msec earlier if middle finger downward.