A mobile electronic device according to an embodiment has an identifier, a determiner, and a permitter. The identifier identifies the operating system of a mobile terminal to which its own device is connected and determines whether the identified operating system is a prescribed operating system. If the identifier determines that the identified operating system is the prescribed operating system, the determiner performs processing to determine whether or not authentication data held in its own device and authentication data held in an authentication data holding device that can communicate via a network match. If the determiner determines that there is a match, the permitter permits data processing using processing data held in a processing data holding device that can communicate via the network.