This report shows the influence of the thermal performance of the bathroom and the bathtub on the temperature change and the bathing patterns based on measured data and a questionnaire results. As a result, it is observed that there is a clear relationship between the thermal performance of bathroom and the terms such as building type. It is also suggested that as for the well- insulated bathtub, temperature drop is suppressed while using the bathtub cover and that the effect was not observed clearly in case without the cover.