A wireless local area network (WLAN) device includes a WLAN adapter having a USB terminal connected to a USB terminal of a PC (personal computer). The WLAN adapter is loaded with a program for setting a WLAN and executing a communication, and a connection of the adapter to the PC prompts the PC to recognize the adapter as a CD-ROM drive, and prompts the program for setting a WLAN and executing a communication to run automatically. The PC loads data of SCSI standard into the WLAN adapter by using a vender defined command of SCSI standard by way of the program for setting a WLAN and executing a communication. The WLAN adapter converts the data of SCSI standard into data for setting a WLAN or data of TCP/IP (Transmission Control Protocol/Internet Protocol), and sets the WLAN and executes the communication.