An novel intraoral inspection apparatus (1) for diagnosing the physiological and pathological status of an in vivo target tissue (30) is described which comprises a light source unit (8) provided with at least one color-producing light source capable of inducing fluorescent lights from healthy and/or diseased sites by irradiating the target tissue. Further a wavelength adjusting device (12) is provided having filter means that transmits a light having a wavelength of a fluorescent light from a predetermined diseased site and blocks or attenuates a light having a wavelength other than this wavelength. An imaging device (17) receives the fluorescent light transmitted through the filter means, and converts them into electrical signals. The apparatus (1) is a hand-held device comprising an elongated body (2) including a proximal end (3) and a distal end (4), the body (2) being configured to position the distal end (4) proximate to the target tissue (30), whereas the light source unit (8) is provided at the proximate end (3), and an optical beam splitter (11) with interferential filters (13) is provided in front of the light source unit (8) to remove unwanted wavelengths and to collimate the light beam into the elongated body (2).
