A spectrum information measurement method may include steps of; controlling a reference pixel accumulating charges based on an amount of light irradiated from a test specimen; controlling a plurality of measurement pixels accumulating the charge based on an amount of light that is irradiated from the test specimen and has a prescribed wavelength; generating and outputting a reference signal based on an amount of change in the charge that is accumulated in the reference pixel over the prescribed measurement time; generating and outputting a plurality of measurement signals based on an amount of change in the charge that is accumulated in each of the plurality of measurement pixels over the prescribed measurement time; determining whether or not any one or more of the plurality of measurement signals is greater than the reference signal, and determining that the measurement signal that is greater than the reference signal includes saturated output.