An examination probe used in an apparatus for examining the depth of a periodontal pocket includes a light-emitting portion and a gripping portion. The light-emitting portion includes a crystal deflecting element, which deflects, in a specific direction, measuring light split off from low-interference light, and an f-θ lens for rendering parallel the measuring light that has been deflected. Measuring light that has been rendered parallel such as a measuring light beam is emitted from an opening of the light-emitting portion and irradiates a gum or tooth of a subject. An optical tomographic image of the gum or tooth is generated from interference signals obtained based on reflected light, allowing the depth of a periodontal pocket to be determined. The light-emitting portion protrudes further than the gripping portion does in the direction of emission of the measuring light such as the measuring light beam.
