An object of the present invention is to prevent the mix-up of subjects and correctly acquire image data of an interior of the subject. An in-vivo information acquiring system according to the present invention includes a portable recording medium (6) on which identification information for identifying a subject (1) is recorded in an erasable manner and a receiving apparatus (3) which receives image data acquired by a capsule endoscope (2) within the subject (1). The portable recording medium (6) is detachably connected to the receiving apparatus (3). The receiving apparatus (3) displays the identification information of the subject (1) read out from the portable recording medium (6), registers the displayed identification information of the subject (1), and erases the remaining registered identification information of the subject (1) in the portable recording medium (6). The receiving apparatus (3) receives the image data, corresponding to the registered identification information, captured by the capsule endoscope (2) in the subject (1).
