In the future lunar exploration missions, global information respect to the origin, the internal structure, and the chemical components is important from the viewpoint of solar exploration. Any system burying the seismometer in the lunar soil is required in order to retain the temperature and improve the coupling with the soil. The authors propose a small burrowing robot for burying it in the lunar soil. In this paper, firstly the authors explain some requirements for the lunar robotic system and discuss the comparison with the other planetary excavation systems. Then the authors present the strategy for subsurface propulsion. Based on the analysis, the authors propose a new type screw drilling mechanism for a burrowing subsurface robot. Through some experiments and theory analysis, the authors evaluate the performances of the proposed system.