The erosion rate map should help to classify the climato-genetic regions in the mountaineous areas. The erosion rate of drainage basins is estimated from the deposition rate of reservoirs. Its regional contrast is especially clear in Tohoku district, northern Japan, as shown in Fig. 1. To draw the map of erosion rate distribution of drainage basins, geology, relief energy and annual precipitation are chosen as effective and realistic factors controlling erosion rate. The equation relating the erosion rate with relief energy and annual precipitation are obtained for three geological groups (Tab. 1, Figs. 2 and 3). The distribution of “the potential energy of erosion” which is defined by the author as R×Pann is shown in Fig. 7. The map of erosion rate in mountains (Fig. 9) is drawn based on the maps of relief energy (Fig. 4), precipitation (Fig. 6) and geology (Fig. 8). All of which are shown in 2'×3' grid system mesh map.