The steep gradient of artificial slopes on forest roads reduces the natural survival rate of vegetation. Uncovered vegetation slopes are exposed, resulting in soil displacement including soil erosion and sedimentation. Therefore, it is necessary to establish an optimized slope management plan with high accuracy for quantifying or detecting the erosion and deposition of artificial slopes. In this context, we investigated the possibility of using a terrestrial laser scanning system (TLS) to estimate soil displacement activity on a cut slope on a forest road. The soil displacement was estimated using time series point cloud data captured by a TLS. The differences among the captured point cloud data were calculated using a digital evaluation model of difference methodology. To validate the performance of the TLS for soil displacement estimation, 10 soil displacement markers were installed in a cut slope. The study revealed that the TLS detected the differences in soil erosion and deposition activity on an area of a steep slope. The differences in soil erosion and the depth of soil sediment were estimated to be 1.36 and 0.3 cm, respectively. The results of this research indicate the feasibility of using a TLS to investigate the surface displacement on a slope area, despite the errors of the estimated erosion and deposition.