To improve high security and power saving efficiency with a simple configuration.

An information processing device capable of shifting to a power saving mode includes a main MPU 101 for controlling a shift or a return to/from the power saving mode, and a LAN I/F 112 for transmitting an information communication signal to the outside. The LAN I/F 112 includes: a reception operation circuit 122b for acquiring an input signal; a ROM 123b for storing an identification (ID) to identify a PC 15 that uses a function provided by the information processing device through a network; and an ID discrimination circuit 123a for acquiring the ID from the acquired signal according to a predetermined protocol, and for outputting a signal instructing to return from the power saving mode, when the acquired ID is stored in the ROM 123b.