An information processing device has a receiving section for receiving, from a second vehicle having started the tracking of a first person, the position information of the second vehicle and the image data photographed by the on-vehicle camera mounted on the second vehicle; a control section for searching for the image of the first vehicle included in the image data from the images photographed by monitoring cameras installed around the position indicated by the position information and for tracking the first vehicle searched for using the images photographed by the monitoring cameras; and a transmitting section for transmitting the tracking position information of the first vehicle being tracked by the control section.