This invention has as its object to allow an authentication process that avoids unnecessary information from being stored in a digital camera irrespective of whether or not a digital camera connected to the printer has a direct print function. To this end, in this invention, in an early stage of connection between a digital camera DSC and PD printer, the PD printer side requests an object which contains a keyword as authentication information of those which are stored and held by the DSC (S29). As a result, after it is determined the returned information contains authentication information, the printer notifies the DSC of its own authentication information (S33).