A body-insertable apparatus is inserted into a subject and obtains information of an inside of the subject. The body-insertable apparatus includes an illuminating unit that outputs an illumination light to illuminate the inside of the subject; an imaging unit that obtains image information of the inside of the subject which is illuminated by the illuminating unit; a radio transmitting unit that transmits information of the inside of the subject by radio; a clock generating unit that generates a clock for obtainment of the image information by the imaging unit; and a correcting unit that corrects a clock for radio transmission by the radio transmitting unit based on the clock generated by the clock generating unit.