An object of the present invention is to actively control at least one of the position and direction of the imaging field in a subject and to observe a desired observed region in the subject certainly in a short period of time. A body-insertable device system according to the present invention includes a capsule endoscope (1) introduced into a subject and a permanent magnet (3). An imaging unit of the capsule endoscope (1) for taking an image inside the subject is fixed in a casing. The capsule endoscope (1) includes a drive unit for changing at least one of the position and posture of the casing in the liquid (2a) which is also introduced in the subject (100). The permanent magnet (3) controls the operation of the drive unit for changing at least one of the position and posture of the casing in the liquid (2a).
