A capsule endoscope includes a capsule-shaped casing and an imaging unit for taking an image of an inside of an organ in a state where the capsule endoscope is floating in liquid introduced inside the organ of a subject. Specific gravity of the capsule endoscope to the introduced liquid is ρ; a plane divides the capsule endoscope such that a volume ratio is to be ρ:1−ρ. A straight line that connects a center of volume of a portion whose volume ratio is ρ and a center of gravity of the capsule endoscope is substantially perpendicular to the plane. The center of gravity is present at a position farther distant from the plane than the center of volume. A surface of a boundary of a field of view that forms an angle of view of the imaging unit and the plane do not intersect outside the capsule endoscope.