An IR-cut filter includes a substrate and an infrared filtering film. The substrate is made of sapphire, and includes a first surface and a second surface opposite to the first surface. The infrared filtering film covers the first surface of the substrate and increases the reflectivity in relation to infrared light, thus filtering out the infrared light. The infrared filtering film includes a number of first high refraction index layers and a number of first low refraction index layers alternately stacked on the first surface of the substrate.