To provide a subterranean surveying apparatus and a subterranean surveying method capable of surveying even buried objects positioned at great depths through the use of Rayleigh waves.

Detectors 11a-11c detect Rayleigh waves generated by the vibrations of a shaking machine 12 installed on the ground G. Detection signals are signal-processed and arithmetically processed to determine the propagation speed and depth of the Rayleigh waves. The vibration frequency of the shaking machine 12 is changed at a location absent of buried objects to determine the propagation depth of the Rayleigh waves for every frequency. At a survey location of buried objects, the shaking machine 12 is made to vibrate at the same frequencies as those when the depth is determined to determine the propagation speed of the Rayleigh waves for every frequency. Then data in which determined depths and determined speeds are related to each other in the way mentioned above is converted into a graph and displayed on a display part 25. An operator of the subterranean surveying apparatus 1 views display content and judges the presence or absence and depths of buried objects.