A front light guide includes a light guide plate, a light source, a functional material layer and a first adhesive layer. The light guide plate has a side surface, a first surface and a second surface opposite to the first surface. The light guide plate has a first refractive index. The light source faces the side surface and configured to emit light into the light guide plate. The functional material layer is disposed at a side adjacent to the first surface, and has a third refractive index. The first adhesive layer is interposed between the light guide plate and the functional material layer so as to adhere the light guide plate with the functional material layer. The first adhesive layer has a second refractive index. The first refractive index is greater than the second refractive index, and the second refractive index is greater than the third refractive index.