Provided is a multi-wave band light sensor combined with a function of infrared ray (IR) sensing including a substrate, an IR sensing structure, a dielectric layer, and a multi-wave band light sensing structure. The substrate includes a first region and a second region. The IR sensing structure is in the substrate for sensing IR. The dielectric layer is on the IR sensing structure. The multi-wave band light sensing structure includes a first wave band light sensor, a second wave band light sensor, and a third wave band light sensor. The second wave band light sensor and the first wave band light sensor are overlapped and disposed on the IR sensing structure on the first region of the substrate from the bottom up. The third wave band light sensor is in the dielectric layer of the second region.