A light source module including a substrate, a plurality of first light emitting diode (LED) chips, and at least one second LED chip is provided. The substrate has an upper surface. The plurality of first LED chips are disposed on the upper surface and electrically connected to the substrate. The second LED chip is disposed on the upper surface and electrically connected to the substrate. A first distance is between a top surface of each of the first LED chips away from the upper surface of the substrate and the upper surface, a second distance is between a top surface of the second LED chip away from the upper surface of the substrate and the upper surface, and the second distance is greater than each of the first distances.