An object of the invention is to capable of reducing the surface tension of liquid that is applied so as to bring a casing into contact with an organ wall, and easily separating a casing from an organ wall even though the casing comes into contact with the organ wall while being floated on a liquid surface in an organ. The specific gravity of a capsule-type endoscope 1 according to the invention is set to be lower than that of liquid in an organ, so that the capsule-type endoscope is floated on a liquid surface S of the liquid. A center of gravity G of the capsule-type endoscope is set to a position deviated from a center C of a casing 2, so that the casing 2 is maintained in a specific floating position while being floated on the liquid surface S. A boundary B between the casing 2 and the liquid surface S is formed within a projection plane Ka, which is obtained by projecting the casing 2 in the specific floating position perpendicularly to the liquid surface S, at a position excluding an outer periphery Kb of the projection plane Ka.
