A spectral characteristic acquiring apparatus is provided which includes: an area dividing part; a spectrum separating part; a light receiving part; and a calculating part, wherein the calculating part includes a transformation matrix storing part that stores a transformation matrix used for calculating the spectral characteristic corresponding to electrical signals of a first diffraction pattern group including two or more adjacent diffraction patterns, and a spectral characteristic calculating part that calculates, based on the electrical signals of the first diffraction pattern group and the corresponding transformation matrix, the spectral characteristic at the locations of the image carrying medium corresponding to the apertures of the first diffraction pattern group.