1. A moving object detection method for detecting a moving object in video by dividing all or part of the moving object in the video into regions, said moving object detection method comprising: accepting pictures included in the video; calculating movement trajectories by detecting motions between two pictures in units of blocks constituting each of the pictures and each including one or more pixels, and concatenating detected motions for all the pictures; calculating distances each indicating similarity between the movement trajectories, for the movement trajectories calculated in said calculating of movement trajectories; performing segmentation by: transforming the distances calculated in said calculating of distances into geodetic distances by combining distances smaller than a predetermined threshold from among the distances calculated in said calculating of distances; detecting a discontinuity point in a distribution of the obtained geodetic distances; and classifying, into one cluster, movement trajectories separate from each other at a geodetic distance smaller than a length indicating the detected discontinuity point; and outputting a result of the segmentation performed in said performing.