Strains of ground surface in many landslide areas have some remarkable features in periods of rainfall and snow melt. Such a strain have considered to be results of creep movements of soil mass soften with water infiltration. In this report, the author treated theoretically the creep movements as the early phase of the landslide. That is, the soil mass in the landslide was modeled two dimensionally as the Bingham's body. The relationships between the dispacement and deformation of the soil mass and its mechanical structure were obtained by the incremental procedure based upon the viscoelastic analysis of the finite element method. So it became clear in the numerical examples that the distribution of the mechanical constants at the slip plane influences the characteristics of the surface strains and the slips, and that the effects of the excavation and the cutting appear more remarkably near the place of the execution.