A medical instrument 1 for observing the interior of a subject to be examined has an image pickup unit 10 for picking up an image of the subject to be examined from a transparent cover member 14 incorporated in the medical instrument, disposes a multi-bladed fan 20 outside an image-pickup field of view of the image pickup unit 10, generates an airflow, prevents adherents such as dirt from sticking to the cover member 14, prevents the adherents from sticking to the observation window of the observation apparatus without obstructing the field of view, and can thereby obtain a clear observed image.
