A person tracking method comprising: causing a processor to specify a group area in a video, as an area where persons (601, 602, 603) within the video are dense; causing the processor to specify a predetermined person (601, 602, 603) within the video; causing the processor to track coordinates of the predetermined person (601, 602, 603) within the video; and causing the processor to determine (S208, S209) a locus of coordinates of the predetermined person (601, 602, 603) within the group area based on coordinates of the predetermined person (601, 602, 603) out of the group area and a number depicted on a clothing of the predetermined person, wherein the coordinates out of the group area include at least coordinates of the predetermined person (601, 602, 603) who enters the group area and coordinates of the predetermined person (601, 602, 603) who leaves the group area, characterized in that: in determining (S208, S209) the locus of the predetermined person within the group area, the processor performs processes of expanding a locus, at the coordinates where the predetermined person (601, 602, 603) enters the group area, in a direction of a velocity of the predetermined person (601, 602, 603), and expanding a locus, at the coordinates where the predetermined person (601, 602, 603) leaves the group area, in an opposite direction to a direction of a velocity of the predetermined person (601, 602, 603). causing a processor to specify a group area in a video, as an area where persons (601, 602, 603) within the video are dense; causing the processor to specify a predetermined person (601, 602, 603) within the video; causing the processor to track coordinates of the predetermined person (601, 602, 603) within the video; and causing the processor to determine (S208, S209) a locus of coordinates of the predetermined person (601, 602, 603) within the group area based on coordinates of the predetermined person (601, 602, 603) out of the group area and a number depicted on a clothing of the predetermined person, wherein the coordinates out of the group area include at least coordinates of the predetermined person (601, 602, 603) who enters the group area and coordinates of the predetermined person (601, 602, 603) who leaves the group area, characterized in that: in determining (S208, S209) the locus of the predetermined person within the group area, the processor performs processes of expanding a locus, at the coordinates where the predetermined person (601, 602, 603) enters the group area, in a direction of a velocity of the predetermined person (601, 602, 603), and expanding a locus, at the coordinates where the predetermined person (601, 602, 603) leaves the group area, in an opposite direction to a direction of a velocity of the predetermined person (601, 602, 603). expanding a locus, at the coordinates where the predetermined person (601, 602, 603) enters the group area, in a direction of a velocity of the predetermined person (601, 602, 603), and expanding a locus, at the coordinates where the predetermined person (601, 602, 603) leaves the group area, in an opposite direction to a direction of a velocity of the predetermined person (601, 602, 603).