Patent ID: 8786699

Claim:
A suspicious person detection device comprising: a person detection unit to be capable of detecting a position of a person on a per person basis; a person tracking unit to continuously trace the person's position detected by said person detection unit; and a suspicious person detection unit to detect a suspicious person on the basis of a tracking result of said person tracking unit, wherein said person tracking unit determines, as an already-authenticated person, a person authenticated when coinciding with a predetermined first condition, and determines, as an accompanying person, a person who coincides with a predetermined second condition related to the already-authenticated person when authenticated, said suspicious person detection unit, when the accompanying person is distanced at a predetermined first distance or longer from the already-authenticated person, issues an alarm, and the predetermined first distance is set based on a difference in velocity vector between the accompanying person and the already-authenticated person, the difference in the velocity vector being defined by a difference in moving velocity and an angular difference in moving direction.