In this study, EEG and muscle activity of 10 university students were measured for 2 minutes at environmental test room of temperature 25[℃], relative humidity 50[RH%], luminance 1,000[lux] and air velocity 0.02[m/sec] when they were closed eye, looking forest picture and looking city picture. α wave generating in the time of relax and comfortable more activated, and high β wave generating in the time of tension and unrest more decreased when subjects saw forest picture then city picture. Also it could suppose that forest picture increase stability of a mental state according to balance of left and right brain was increased when subjects saw forest picture.