The purpose of this study is to understand the indoor thermal environment in the earth brick wall building what is called a ecological Architecture. To investigate thermal performances of the earth brick walls, it measured indoor and outdoor air temperature, relative humidity, globe temperature and PMV in reference house. The result of this study were summarized as the followings; 1) When the outdoor average air temperature was $21.8^{circ}$, livingroom was $24.9^{circ}$, kitchen was $25.1^{circ}$ and 2nd floor room was $25.6^{circ}$ at 150 cm height from the floor. 2) Although the average outdoor relative humidity was 78%, the livingroom was 67.5%. 3) As the air temperature difference between at the top and bottom was $0.6^{circ}$ in living room, this value was below 1 % of PPD by ASHRAE Handbook. 4) Predicted Mean Vote(PMV) by ISO-7730 was +0.41.