Provided is an in-vivo image capturing system capable of capturing images only in a desired imaging direction within a subject. A monocular capsule casing (62) capable of capturing images only in a direction of one end analyzes image components captured by the imaging optical system within an oral cavity, and a warning about a direction of the capsule casing (62) is issued to a user based on the analytical result. Accordingly, white-tinged or high-brightness image components are obtained when the imaging direction is heading for the teeth side, red-tinged or deep red image components are obtained when the imaging direction is heading for the throat side. Thus, the image components of the both portions are different, thereby allowing determination of the swallowing direction of the capsule casing (62) to the oral cavity. When the swallowing direction is not a desired imaging direction, the warning is issued to makes the user turn the swallowing direction of the capsule endoscope. This makes it possible to obtain images in the desired direction in the monocular type.
