A sensor unit (100) provided with a substrate (101), a plurality of light-receiving units (102) that are provided on the substrate (101) and detect light, and a diffraction grating layer (103) that is provided on the substrate (101) and the light-receiving units (102) and has at least two diffraction means for diffracting light of corresponding wavelengths and condensing the light onto the light-receiving units, wherein at least two of the diffraction means are composed from holograms formed on a first diffraction grating layer and at least a portion of the plurality of holograms formed on the first diffraction grating layer overlap at least partially with another adjacent hologram.