A brightness colorimeter having a measurement error caused by linearly polarized light, which is corrected, includes: a lens module to which light irradiated from one side is input; a polarization conversion module configured to intersect the light input through the lens module to convert polarization characteristics; a spectral module provided in one unit block to reflect and intersect the light input through the polarization conversion module so as to branch the light in different three directions; filter modules arranged on progress paths of the light branched in different three direction through the spectral module to intersect monochromatic light beams having specific spectra among the light branched in the three directions; and measurement modules arranged to correspond to exit angles of the monochromatic light beams penetrated through the filter modules, to measure at least one of a brightness, a chromaticity, and an error obtained by the monochromatic light beams.