An image collating center has a communication unit, a processing unit, and a memory unit. The processing unit accesses a geographic information database through a communication network, extracts appropriate geographic information from the geographic information database based on a picked-up image and additional information transmitted from an image provider, and generates a simulated image assumed to be viewed from the image provider. Further, the image collating center estimates the image pickup position and the image pickup attitude of the image provider through collating the simulated image with the picked-up image and returns the estimated image pickup position and image pickup attitude of the image provider to the image provider through the communication network.