This study analyzed indoor and outdoor thermal performance among different types of green roofs and green walls in order to provide information for building greening. When temperature reduction effects of green roofs and green walls were compared to the control, the effects was highest at the green roof and wall treatment, followed by green wall, green roof, and the control, which means there was temperature reduction effects by building greening. Also these temperature reduction effects was influenced by outdoor weather condition such as being typically high in sunny days but not notable in rainy days. In addition temperature reduction was effective as the air temperature was up but was not influenced by wind velocity. As for directions, the west side showed the highest temperature followed by the south and east in the order. Heat flow was found greater in control than in green roof and green wall. In addition, heat flow reversal was found as time went on.