To avoid increase in burden of management business on a network administrator, and deterioration in security even in an environment where a mediation device performs communication with each electronic apparatus in different communication modes.

The CPU 44 of a communication adapter (mediation device) 21 presets the execution sequence of communication in each of a plurality of communication modes including a security communication mode (transport mode, tunnel mode of IPsec communication mode) for use in apparatus search. Communication in each communication mode with each electronic apparatus registered as an apparatus to be managed is executed sequentially, and the apparatus search for acquiring the apparatus information from each electronic apparatus in an available communication mode is performed. The apparatus information acquired by the apparatus search is associated with the communication mode at the time of acquiring the apparatus information, and held in an RAM 46 as the communication related information.