Abstract: A fog light device has a base casing, a lampholder, a transparent lampshade, a photoconduction plate, an outer casing, a main bulb, and at least an auxiliary bulb. The base casing has a hollow interior to receive at least a positioning seat. The auxiliary bulb is connected to the positioning seat. The main bulb is inserted in the center through hole of the lampholder. The transparent lampshade is inserted in the annular recess of the lampholder. The photoconduction plate is inserted in the annular channel of the lampholder. The photoconduction plate has a first taper end and a second taper end to receive a light emitted by the auxiliary bulb.