A spectral characteristic acquisition device, comprising: a light irradiation part comprising a line illumination light source configured to irradiate an object with light; a diffraction part configured to diffract light reflected from the object to provide diffracted light; a light-receiving part configured to receive the diffracted light and output a signal based on an amount of the diffracted light; a calibration unit as a calibration color index configured to include a plurality of colors with known spectral characteristics and to include a reference white part; and an operation part configured to calculate a spectral characteristic of the object from a signal output from the light-receiving part by using a predetermined transformation matrix, to calibrate the transformation matrix by using the calibration color index, and to correct a signal output from the light-receiving part by using the reference white part, characterized in that the calibration unit includes a columnar member, wherein the calibration color index is provided on an outer peripheral surface of the columnar member, and in that the calibration unit is rotatable and covered with a rotatable cover member of a cylindrical shape with an aperture, wherein the aperture is configured such that it is possible to expose at least a portion of the calibration unit to the line illumination light source when the cover member rotates, and the operation part is further configured to correct a signal output from the light-receiving part by using the aperture, wherein the cylindrical surface of the rotatable cover member covers the calibration unit at a lower side of a supporting plate that supports a measurement object to be conveyed or mounted thereon, said supporting plate being provided with an aperture in such a manner that it is possible to expose at least a portion of the calibration unit to the line illumination light source. a light irradiation part comprising a line illumination light source configured to irradiate an object with light; a diffraction part configured to diffract light reflected from the object to provide diffracted light; a light-receiving part configured to receive the diffracted light and output a signal based on an amount of the diffracted light; a calibration unit as a calibration color index configured to include a plurality of colors with known spectral characteristics and to include a reference white part; and an operation part configured to calculate a spectral characteristic of the object from a signal output from the light-receiving part by using a predetermined transformation matrix, to calibrate the transformation matrix by using the calibration color index, and to correct a signal output from the light-receiving part by using the reference white part, characterized in that the calibration unit includes a columnar member, wherein the calibration color index is provided on an outer peripheral surface of the columnar member, and in that the calibration unit is rotatable and covered with a rotatable cover member of a cylindrical shape with an aperture, wherein the aperture is configured such that it is possible to expose at least a portion of the calibration unit to the line illumination light source when the cover member rotates, and the operation part is further configured to correct a signal output from the light-receiving part by using the aperture, wherein the cylindrical surface of the rotatable cover member covers the calibration unit at a lower side of a supporting plate that supports a measurement object to be conveyed or mounted thereon, said supporting plate being provided with an aperture in such a manner that it is possible to expose at least a portion of the calibration unit to the line illumination light source.