A few systematic researches on the nature, water resource and conservation of river-head area, namely the heart of mountaineous region, have been reported during many years in Japan.<BR>But wonderful growth of our cities and industries are calling for outstanding demands on the nature and environment. Therafore, to aquire reliable information on the nature of basins, some of which are now mortally injured, is an urgent and practical problem for the assessment of natural environment and the planning of various conservation methods of basins.<BR>To meet with these practical interests, an allover plan as shown in Fig. 1 was projected choosing the river-head area of Kurobegawa as our research field and a part of it (Thermal environment and heatbelance system) was carried out in the midsummer, 1975. The results obtained are summerized as follows:<BR>(1) Comparison between the meteorological conditions of Toyama plane (at Toyama Local Meteorological Observatory) and those of mountain (at Kumonodaira-plateau) was made as be shown in Fig. 5.<BR>(2) Horizontal distribution of the surface temperature of the river-head area of Kurobegawa at ca. 9: 30 a. m. was examined by means of remote sensing as illustrated in Fig. 6. The figure tells us the following facts that:<BR>(a) At that time (9: 30), so wide temperature range from 0°-30°C, occurred in this area.<BR>(b) Horizontal heat transfer from the border line of the unmelted snow cover to the center part of it was noticed.<BR>(c) As the incident short-wave radiation is the leading factor of soil temperature fluctuation, the inclination and the orientation of the slope play the important role in forming the horizontal temperature distribution of soil surface as illustrated in Fig. 7.<BR>(d) The surface temperature variation of the sloped land having arbitrary inclination and orientation was greatly affected by the vegetable cover as illustrated in Fig. 8.<BR>(e) Considering from (c), the two areas having quite different surface temperature can be contiguous to each other, and the center line of that is the ridge of mountains as shown in Fig. 6.<BR>(f) The temperature difference between the adjacent two areas affects the character of the local climate of mountains.<BR>(3) Radiation balance in the mountains (at Kumonodaira-plateau) was analyzed as shown in Fig. 9.<BR>(4) Hourly heat-balance on Kumonodaira-plateau was calculated as shown in Table 2 and the following relations were obtained on the daily basis, ΣlE/ΣR_n≈0.63, ΣF/ΣR_n≈0.32.