Widening an angle of view, and obtaining a clear image with no distortion by sufficiently correcting an aberration caused by widening the angle of view. A capsule endoscope 10 is provided with an imaging lens 20, capsule body 22, and a transparent cover 23. The capsule body 22 is formed hollow, and has an opening 22b at its end 22a. The imaging lens 20 is provided such that a part thereof is positioned inside the capsule body 22 and the rest is protruded from the opening 22b. The transparent cover 23 is formed into a dope shape, and is attached to the end 22a of the capsule body 22 to cover the imaging lens 20 protruded from the opening 22b. The inside of a patients body is captured using the transparent cover 23 and the imaging lens 20 designed to satisfy the following condition: f D /f L ‰¤70where f D is a focal length of the transparent cover 23, and f L is a focal length of the imaging lens 20.
