Comparing with an upper generation who have experienced a living with a extended family in a sudden aged tendency, the Parent & Children generation who haven't had a experience in it. So they have much different life styles each generation. It may cause many problems that many generation are living in a common residential space. Further more every generation gets their own characteristic of the life style. In addition, the middle & lower generations's understanding can be explained on their position about an Grand-parent generation's using. In this study, I am going to find out the problems in these situation in comparison with each generation's understanding dwelling environment among them, and then analyze what affection of 3-generation sharing preference standard is given by the differences each generation have with the above result. The standard of living with an Grand-parent generation ; Children generation or living separately through evaluating the Parent & Children generation's residence surroundings will be estimated and the standard of importance of sharing house will be analyzed. And then the result will be used as basic information of planning the 3-generation sharing house.