Abstract: A spectrum display device for displaying in colors a spectrum obtained by a scientific instrument such as a mass spectrometer in which video signals for producing two colors are supplied to a color display device such as a CRT, for example, a video signal for producing a red color contains information with respect to a first spectrum and a video signal for producing a blue color contains information with respect to a second spectrum, and therefore a region on a display face where the first and second spectra coincide with each other assumes a magenta color when the video signal for producing the red color and the video signal for producing the blue color are simultaneously supplied to the color display device. Accordingly, this spectrum display device makes it possible to perceive the degree of coincidence between the two spectra by a mixed color and to perceive a difference between the two spectra by the two original colors.