A position detection apparatus for detecting a position of a capsule endoscope in a subject based on reception strength of a signal at a plurality of receiving antennas that is transmitted from the capsule endoscope configured to be introduced into the subject to move inside the subject, the position detection apparatus comprising: a distance calculation unit configured to calculate a first distance (r n) between each of the plurality of receiving antennas and the capsule endoscope based on each reception strength of the signal received by the plurality of receiving antennas; a total distance calculation unit configured to: set a plurality of subregions obtained by dividing a region inside the subject where the capsule endoscope possibly exists; calculate a second distance (d mn) which is a distance between a center point of each of the plurality of subregions and each of the plurality of receiving antennas; determine whether the center point of each of the plurality of subregions is positioned inside a region where at least three or more out of a plurality of spheres are overlapped, each of the plurality of spheres having a center at each of the plurality of receiving antennas and having a radius of the first distance (r n), based on whether or not the second distance (d mn) is equal to or shorter than the first distance (r n); calculate, for each of the receiving antennas corresponding to the at least three or more spheres, differences between the first distance (r n) and the second distance (d mn) with respect to the center point of at least one of the plurality of subregions which has been determined to be positioned inside the region where the at least three or more spheres are overlapped, when the second distance (d mn) is equal to or shorter than the first distance (r n); and acquire a total sum of the calculated differences; and a position determination unit configured to detect, as the position of the capsule endoscope, a position where the total sum of the calculated differences is minimum. a distance calculation unit configured to calculate a first distance (r n) between each of the plurality of receiving antennas and the capsule endoscope based on each reception strength of the signal received by the plurality of receiving antennas; a total distance calculation unit configured to: set a plurality of subregions obtained by dividing a region inside the subject where the capsule endoscope possibly exists; calculate a second distance (d mn) which is a distance between a center point of each of the plurality of subregions and each of the plurality of receiving antennas; determine whether the center point of each of the plurality of subregions is positioned inside a region where at least three or more out of a plurality of spheres are overlapped, each of the plurality of spheres having a center at each of the plurality of receiving antennas and having a radius of the first distance (r n), based on whether or not the second distance (d mn) is equal to or shorter than the first distance (r n); calculate, for each of the receiving antennas corresponding to the at least three or more spheres, differences between the first distance (r n) and the second distance (d mn) with respect to the center point of at least one of the plurality of subregions which has been determined to be positioned inside the region where the at least three or more spheres are overlapped, when the second distance (d mn) is equal to or shorter than the first distance (r n); and acquire a total sum of the calculated differences; and a position determination unit configured to detect, as the position of the capsule endoscope, a position where the total sum of the calculated differences is minimum.