A backlight module includes a circuit board, a light-shielding plate, and a light guide plate. The circuit board is provided with first and second light-emitting units. The light-shielding plate is disposed above the circuit board. The light guide plate is disposed between the circuit board and the light-shielding plate and includes first and second single-key light guide areas. The first and second single-key light guide areas respectively have first and second through holes respectively accommodating the first and second light-emitting units. A distance between the geometric center of the first single-key light guide area and that of the light guide plate is greater than a distance between the geometric center of the second single-key light guide area and that of the light guide plate. A current flowing through the first light-emitting unit is greater than a current flowing through the second light-emitting unit.