An information processing device includes a processor configured to: receive first positional information related to a position of a portable device from the portable device; extract transmitters located within a certain area including a first positional coordinate, which is a positional coordinate of the portable device based on the first positional information, from among registered transmitters, calculate respective distances between transmitters within the certain area and the portable device, and extract a predetermined number or less of transmitters based on the calculated distances from among the transmitters within the certain area; and transmit first identification information of the predetermined number or less of transmitters, which allows the portable device to determine whether the first identification information includes second identification information indicating a transmitter transmitted from the transmitter in and to perform a particular process when the first identification information includes the second identification information, to the portable device.