The frame format is a frame transmitted from the mobile terminal 300 to the information server 500 through the wireless network 410 and the Internet 430 to collect information regarding IoT devices 100. The transmission frame for information collection includes a synchronizing signal 651 followed by transmission destination server unique information 652, transmitter device unique information 653, current-position information 654, the number (N) 655 of detected surrounding IoT devices, and device information 656 on each of the N devices that are added to the synchronizing signal 651. Furthermore, an error detection code 657 is added to the end.

Here, position information parameters of the current-position information 654 include device latitude information 661, device longitude information 662, device altitude information 663, device orientation information 664, and the like.

Furthermore, the device information 656 on each of the devices includes collected information 666, collection day and time information 667, a collected arrangement position 668, a signal strength 669 of a received signal, and the like. The device information 656 on each of the N detected devices is connected together.

The information server 500 that has received the frame stores the device information 656 as attribute information on the IoT devices 100.

Note that the above parameters are only exemplified, and addition or deletion may be performed as necessary.