The required minimum amount of examination site information is acquired, stored, or transmitted without missing an affected area, thus reducing power consumption, reducing the size of a battery disposed in a capsule, and reducing the size of a casing. Provided is a capsule medical device (1) including a casing (2) having a capsule shape a light-detecting section (4), disposed in the casing (2), for detecting information about the intensity of light from outside the casing (2) an information-acquiring section (5) for acquiring examination site information from an examination site positioned outside the casing (2) and a determination section (8) for determining whether or not to acquire, store, or transmit, to the outside, the examination site information acquired by the information-acquiring section (5) on the basis of the information about the intensity of the light detected by the light-detecting section (4).
