Universal serial bus device

A USB device includes a base, a circuit board disposed on the base and having front-end and rear-end portions and a ground circuitry, an upper cover, solder points, a switch and a button mount. The rear-end portion is used for inserting into a connection port of a computer terminal. The upper cover covers the front-end portion and has an opening. The solder points are formed on the front-end portion and coupled to the ground circuitry. The switch having a metal cover is welded at the solder points for controlling wireless connection between the computer terminal and an external device. The button mount is movably disposed through the opening and sleeves the front-end portion for triggering the switch. Electrostatic discharge entering from the opening can pass through a first guide hole of the button mount and is conducted to the ground circuitry via the metal cover and the solder point.