A light pulse multiprocessing unit has a half mirror and N delay elements, each having a refractive index n. The N delay elements are arranged on one side of the half mirror from one end of the half mirror toward the other end and have thicknesses Δ, 2Δ, . . . , 2N−1Δ different from each other, where Δ is the smallest thickness. The half mirror is placed in parallel in the proximity of an intermediate position between two mirrors and the N delay elements are arranged between one of the mirrors and the half mirror. Each of the N delay elements is a plane-parallel plate and is placed at an angle such that the direction of the normal line of the surface of the plane-parallel plate is different from a direction followed from one end of the half mirror toward the other end.