In order to clarify spatial variations in a river bed form in a granitic mountainous catchment, we surveyed topographically a steep river on a source area of Kurose River in which the debris flow occurred in 1999. Firstly, we found that the spatial variation in erosion-deposition process on the steep river. Both of the lower stream and upper one held much sediments with large gravels (φ>2m). On the other hand, the middle stream exposed mainly the bedrock. Secondary, we confirmed spatial distribution of river falls. The height of river fall on the upper stream rose with the increase of river gradient. On the contray, the frequency of falls was constant in spite of inclination.