In a position authentication system and electronic equipment used for the same, image data photographed by a digital camera 1 are written into storage device 3, and at the same time GPS electric wave 5 is received by GPS receiver 2 to generate latitude/longitude information. The GPS receiver 2 encrypts the latitude/longitude information, and transmits this information as position information to center system 4. The storage device 3 stores copy-guarded place-specifying data transmitted from the center system 4. The center system 4 decodes the position information 6 input from the digital camera 1, and specifies the place on the basis of the latitude/longitude information thus obtained to generate place-specifying data. The place-specifying data thus generated are subjected to copy guard-processing and then transmitted to the digital camera 1. Accordingly, it is guaranteed that the image data stored in the storage device 3 was photographed at the place indicated by the place-specifying data and the image data was not photographed at another place.