A USB-compliant keyboard device is provided that is capable of preventing malfunctions, operation failure and the like due to static noise by a simple method. The keyboard device has a keyboard main body with a large number of key tops on its upper surface, an upper case and a lower case accommodating the keyboard main body, a control circuit board on which a control circuit to control the keyboard main body is mounted, and USB connectors connected to the control circuit board. Further, a shield plate covering the control circuit board from a lower position is provided. The shield plate is electrically connected to frame ground members of the USB connectors and a shield line of a cable connected to a personal computer main body.