An electronic device includes a casing, a circuit board and a grounding assembly. The circuit board has a first surface and a second surface, wherein an input terminal and an output terminal are disposed on the second surface. The grounding assembly comprises a conducting terminal, a first grounding element and a second grounding element. The conducting terminal is disposed on the first surface of the circuit board, and the first grounding element is disposed adjacent to the conducting terminal. The first grounding element penetrates the circuit board and electrically couples with the conducting terminal and the casing, and the second grounding element correspondingly penetrates the circuit board and the conducting element, so that a first portion of the second grounding element electrically couples with the input terminal and the output terminal of the circuit board, and a second portion of the second grounding element electrically couples with the conducting terminal.