The seismic refraction method has been widely used in many tunnel projects in mountainous areas. However, it is sometimes difficult to apply this way to the complicated geological feature of Japan, too. This is said to be utilized efficiently and for there to be no limit and geology information on investigation.<BR>Then, writers noted the point currently used abundantly in the construction stage evaluating cutting-face. And it was presupposed that adjustment of a geological survey is evaluated by the same item as cutting-face evaluation. After we evaluated three tunnels using this method, it was possible to judge about the high precision.