A voltage conversion device having a circuit board and a metal shielding cover are provided in this disclosure. The circuit board has a front surface and a back surface. The front surface of the circuit board is provided with a transformer circuit and an assembling terminal electrically connected to the transformer circuit. A through hole is defined at a position on the circuit board corresponding to the assembly terminal. The back surface of the circuit board is covered by the metal shielding cover, and the metal shielding cover is provided with a conductive pin corresponding to the assembling terminal. The assembling terminal is provided with a clamp, and the clamp is arranged corresponding to the position of the through hole. The conductive pin passes through the through hole and clamped by the clamp, and the metal shielding cover is thereby fixed on the circuit board.