Property information of image data sets managed in an image data management apparatus can be dealt with according to a characteristic thereof, while efficiency of use can be improved. Image ID is issued for each of the image data sets uploaded by a user. Property information A and B is respectively obtained by analysis of the image data sets and by an input from the user. The user can set a security processing method and a storage method for each of items of the property information. The items of the property information whose storage method has been set to image data attachment are attached to the image data sets while the remaining items whose storage method has been set to database storage are separately stored together with the image ID, after the security processing according to the security processing method.