It is important to create a comfortable environment to restful sleep. In this study, we trial-produced an in-bed temperature control system. At first, we statically controlled the temperature in the subject's bed at 32°C by using the system, and examined how this control affected sleep. We were able to confirm that the ratio of slow-wave sleep (SWS) increased in comparison to cases in which the temperature in the bed was not controlled. Next, the temperature in the subject's bed was dynamically controlled at temperature change patterns according to sleep cycles that is as follows; Heating during the REM sleep period and cooling during the SWS sleep period were conducted n the range of 32±2°C, and the case of the opposite phase. The result showed that cooling during the REM period increased the REM sleep share rate. Based on these results, an increase of the REM sleep share rate at around 30°C could be confirmed, indicating a possibility that the REM period thermoneutrality zone shifted to a lower temperature, compared with that of SWS.