As transformed to aging society rapidly, the number of old persons who live alone is drastically increased. Because these old people may have disorder of bodily function, and be suffering from geriatric disease, needs of a health assistance system to make them healthier are strongly increased. In this paper, we propose a daily activity recognition system for an old person using pressure sensors. The target daily activities are MEAL, SLEEP, EXCRETION, GO-OUT, and REST. The proposed system installs pressure sensors to furniture and floors in home, and recognizes daily activities based on the object usage information. By using the proposed system, we can provide a warning sign for unhealthy cases such as skipping meals. And, the families who live in remote place can check that their parent takes a healthy daily living.