An object of the present invention is to achieve power reduction of a body-insertable apparatus to extend the operation time of the body-insertable apparatus. A capsule endoscope according to the present invention selects an in-vivo image to be added with predetermined unique information from the in-vivo images captured by an imaging unit, additionally arranges an identification signal ID, which is written in accordance with a signal sequence rule of the vertical synchronization signal VD and the horizontal synchronization signals HD, to only the selected image G11, in a position corresponding to the positions in which the vertical synchronization signal VD and the horizontal synchronization signals HD. The capsule endoscope then transmits the image information added with the unique information corresponding to the identification signal ID after the identification signal ID. Therefore, it is possible to reduce the amount of data to be transmitted and thus to achieve power reduction and extend the operation time, compared with the conventional method that transmits image information all added with unique information.
