This study is on the elderly people's use and experience of a wearable device. By using wearable device, the elderly can monitor their health data at real time. As a result, their motivation for health care, exercise, and so on can improve and enhance. Across the globe, population aging becomes one of the most important problems in each nation. The social and economic burden from aging is one of most serious challenges to sustainability of the world and its economy, including South Korea. Information Communication Technology including wearable device can help the elderly health care improve. In 2016, the number of wearable devices is more than 19 million. Many of them are the devices related to health data monitoring. In the experiment, the authors measure real time health data from the subjects' wearable devices. In the first experiment day, subjects' average waist size was 36.29 inches. In the final experiment day, 31st day later from start of the experiment, the average waist size was 35.51 inches. At the beginning of the experiment, standard deviation was 1.93. At the final day of the experiment, it was 2.24. In regression analysis, when experiment day extends, average waist size seems to decrease. The trend is significant (t=2.719, p<0.05). That result may mean the subjects' motivation for health care improve. Wearable device can increase the elderly people's motivation for health care and exercise. As a result, their health can improve.