The present disclosure provides a construction management system capable of ascertaining information about a construction site more accurately than before. A construction management system 100 comprises: a position sensor 16a detecting position information about a transport vehicle 10 that transports payload; a position sensor 26 detecting position information about a loading machine 20 that loads payload onto the transport vehicle 10; a weight detection device 120 detecting weight information about the payload held by the loading machine 20; and an information management controller 130 which, based on chronological information of the position information about the transport vehicle 10, chronological information of the position information about the loading machine, and chronological information of the weight information, calculates the load weight of the payload loaded onto the transport vehicle 10.