An antenna holder includes: an antenna attachment portion attached with a plurality of receiving antennas configured to receive wireless signals transmitted from a medical device introduced into a subject； and a fitting portion where the antenna attachment portion is detachably attached and that is fitted on the subject. The antenna attachment portion includes: a plurality of antenna fixing portions where at least one of positions of the plurality of receiving antennas is fixed； an interlinking portion configured to variably interlink relative positions of the plurality of antenna fixing portions； and a first attachment portion attached to the fitting portion. The fitting portion includes: a second attachment portion where the first attachment portion is detachably attached, the second attachment portion being configured to determine positions of the plurality of antenna fixing portions upon fitting of the plurality of antenna fixing portions on the subject, according to build of the subject.
