At present, the Great Sphinx as one of the most important World Heritages is being seriously subjected to a remarkable weathering and deterioration. Aiming at contributing to the restortion work for the Great Sphinx, authors are carrying out site investigation in order to clarify water budget between the bedrock and the air where weathering and deterioration are taking parts. In this paper, the application of the electrical prospecting (resistivity method) was illustrated. As a result, the distribution and the daily cyclic change of the moisture in the bedrock were confirmed by monitoring the electric resistivity of the rock at the site.