To provide a device capable of surely performing establishment of communication with a host while suppressing an increase in cost.

In a USB device 100 performing communication by USB2.0 standard, in which High Speed mode is set via Full Speed mode, whereby communication is performed while recognizing the setting to the High Speed mode, the communication mode is set to High Speed mode by a mode setting means 30 until communication preparation with a host 200 is completed after inputting power supply.