Control of indoor thermal environments in accordance with people's preferences, makes an important contribution to comfort. To keep a suitably temperate environment, we tried to estimate a subject's thermal sensation using biologic signals. We focused on peripheral skin temperature to estimate individual thermal sensation. First we carried out an experiment involving an alteration of environmental temperatures to reveal the relationship between peripheral skin temperature and thermal sensation votes. Next we made an algorithm of estimating thermal sensation and assessed the algorithm. When thermal sensation indices estimated by our algorithm were compared with the subject's votes, error of mean squares was 1 or less in most cases. As a result, the possibility of thermal sensation measurement using peripheral skin temperatures is confirmed. Furthermore, we implemented the temperature control system using a household air conditioner and a thermal sensor.