A moving object tracking apparatus (20; 20-2) comprising: an acquiring unit configured to acquire a plurality of pieces of moving object information representing a moving object included in a plurality of photographed images photographed by a plurality of imaging units ; an associating unit (212; 212-2) configured to calculate a degree of similarity of appearance using feature values representing appearances of moving objects and execute an associating process based on the degree of similarity, the associating process being a process for associating a plurality of pieces of the moving object information similar to each other as the moving object information of the same moving object for three or more pieces of the moving object information; and an output control unit (213; 213-2) configured to output the associated moving object information, wherein each of the plurality of imaging units belongs one or more groups out of a plurality of groups; each of the plurality of pieces of moving object information is classified into a group to which a corresponding imaging unit belongs, and the associating unit (212; 212-2) includes an intra-group associating unit (221-1; ...; 221-m) configured to execute the associating process for the moving object information included in the group, and an inter-group associating unit configured to execute the associating process for the moving object information associated by the intra-group associating unit (221-1; ...; 221-m). an acquiring unit configured to acquire a plurality of pieces of moving object information representing a moving object included in a plurality of photographed images photographed by a plurality of imaging units ; an associating unit (212; 212-2) configured to calculate a degree of similarity of appearance using feature values representing appearances of moving objects and execute an associating process based on the degree of similarity, the associating process being a process for associating a plurality of pieces of the moving object information similar to each other as the moving object information of the same moving object for three or more pieces of the moving object information; and an output control unit (213; 213-2) configured to output the associated moving object information, wherein each of the plurality of imaging units belongs one or more groups out of a plurality of groups; each of the plurality of pieces of moving object information is classified into a group to which a corresponding imaging unit belongs, and the associating unit (212; 212-2) includes an intra-group associating unit (221-1; ...; 221-m) configured to execute the associating process for the moving object information included in the group, and an inter-group associating unit configured to execute the associating process for the moving object information associated by the intra-group associating unit (221-1; ...; 221-m). an intra-group associating unit (221-1; ...; 221-m) configured to execute the associating process for the moving object information included in the group, and an inter-group associating unit configured to execute the associating process for the moving object information associated by the intra-group associating unit (221-1; ...; 221-m). <EOS>