A body-insertable apparatus includes: an illuminating unit that illuminates the inside of a subject's body; an imaging unit that takes an image of the inside of the subject's body; a first power supplying unit that supplies electric power to the imaging unit; a second power supplying unit that supplies electric power to the illuminating unit; and a switch that either connects the first power supplying unit to the second power supplying unit or disconnects the first power supplying unit from the second power supplying unit. The switch electrically separates the first power supplying unit from the second power supplying unit during at least an illuminating period of the illuminating unit.