An antenna apparatus is configured to acquire information from a body-insertable apparatus that is configured to be inserted into a subject to move inside the subject. The antenna apparatus includes an antenna that includes one sheet on which plural receiving antennas are fixed and in which a first positioning hole is formed; and an antenna holder that includes a container portion which is configured to hold the antenna at a predetermined position and in a predetermined orientation and in which second positioning hole is formed at a position corresponding to the first positioning hole when the antenna is held. The antenna holder is configured to be attached to a predetermined position of the subject using the first and second positioning holes as an index when the antenna is held in the antenna holder.