A system includes a capsule body having a casing introduced into a subject to perform, in liquid, examination of or treatment on the interior of the subject, the casing containing a permanent magnet, a mass of the casing excluding the magnet being set to be less than a product of a volume of the casing and a density of the liquid a magnetic field generator that generates a magnetic attraction for the magnet to guide the capsule body and a magnetic field generation device that controls the magnetic field generator to generate the magnetic attraction by setting a maximum value of the generated magnetic attraction vertically upward to the capsule body, to be equal to a maximum value of the generated magnetic attraction vertically downward to the capsule body, and by setting the maximum values to be less than a value obtained by multiplying a mass of the magnet by a gravitational acceleration.
