Provided is a system that can appropriately keep watch over pedestrians. The abnormal state detection device according to one aspect of the present invention is provided with: an image acquisition unit that acquires photographed images that capture a pedestrian walking and that include depth data that indicates the depth of each of the pixels in the photographed images； an extraction unit that extracts a person region that is the region in which the pedestrian appears in the photographed images； a movement measurement unit that references the depth of the pixels included in the extracted person region and, by continuously specifying the position in real space of a local site that is an observation target on the body of the pedestrian that appears in the photographed images, measures the movement in real space of the local site； a status determination unit that determines whether the pedestrian is in an abnormal state on the basis of the measured movement of the local site； and a notification unit that, when the determination results have determined that the pedestrian is in an abnormal state, performs abnormality detection notification that is for making it known that the pedestrian is in an abnormal state.L'invention concerne un système permettant de surveiller des piétons de manière appropriée. Selon un aspect de la présente invention, le dispositif de détection d'état anormal comprend : une unité d'acquisition d'images qui acquiert des images photographiées qui capturent un piéton en train de marcher et qui comprennent des données de profondeur qui indiquent la profondeur de chacun des pixels dans les images photographiées ； une unité d'extraction qui extrait une région de personne qui consiste en la région dans laquelle le piéton apparaît dans les images photographiées ； une unité de mesure de mouvement qui référence la profondeur des pixels inclus dans la région de personne extraite et, en spécifiant de manière continue la position dans l'espace réel d'un site
