An information collection system 1 has: a stand-alone-power-type transmitter 10 capable of moving together with a mobile entity (purchaser) A1, the transmitter 10 spontaneously and intermittently transmitting a transmitter ID at a timing corresponding to the distance of movement of the mobile entity A1; a plurality of receivers 20 provided in an area X to be monitored in which the mobile entity A1 can move freely, the receivers 20 receiving the transmitter ID transmitted from the transmitter 10 present in the vicinity of the area X; and a server 30 for managing the transmitter ID, the position information (receiver ID) of the receiver 20 that receives the transmitter ID, and a time of day at which the receiver ID is received, in association with each other.