An RTK-GPS surveying system for surveying an object includes at least one satellite positioning device as a base station configured to send correction data, a plurality of satellite positioning devices as rover stations configured to receive the correction data, and a server provided in an IP-VPN communication network for establishing communication between the satellite positioning device as the base station and the plurality of satellite positioning devices as the rover stations, each of the satellite positioning devices has a satellite positioning part for receiving radio wave from a satellite, a communication part for performing communication between each of the satellite positioning devices, and a control part for controlling the satellite positioning part and the communication part.