A capsule endoscope 2 includes a partial-image acquiring unit that has a field of vision of 360° around a central axis in a longitudinal direction (moving direction), and acquires a plurality of partial image data on inner circumferential areas 28a, 28b and the like according to a movement of the capsule endoscope 2. On the other hand, the capsule endoscope 2 is configured to acquire position related data based on which positions Z(t1) and Z(t2) at which the respective partial image data is acquired can be calculated, and enables a receiving apparatus or the like to constitute overall image data based on the partial image data and the position related data, whereby an overall image of a predetermined imaging target in a body of a subject is acquired with simple constitution while suppressing an increase in data amount.