A USB circuit device prevents reverse current while complying with USB specifications. A USB circuit device includes a connector unit to which a USB device is connected; a power supplying unit supplying power with the USB device through the connector unit; a switching unit flowing current induced into the connector unit from the USB device, into a ground selectively; and a controller controlling the switching unit to flow the current induced into the connector unit, into the ground if a level of the power provided with the USB device by the power supplying unit is less than a predetermined value. Accordingly, there is provided a USB circuit device for preventing reverse current from an external device and capable of protecting the circuit from over current with satisfaction to a USB specification.