A multi-spectrum image capturing device includes a multi-spectrum illuminating device comprising LED's for emitting lights of different wavelengths from one another, a plurality of optical rods for relaying the lights emitted from the LED's, an optical diffusion element for diffusively reflecting the lights from the optical rods by a white diffusion surface and an aluminum-coated reflecting surface to be irradiated at an angle of about 60° with respect to an image-capturing optical axis, and an optical sheet for further diffusing the lights from the optical diffusion element, and also includes an image-capturing optical system and a CCD for forming an image based on lights reflected from an irradiated surface under illumination by the multi-spectrum illuminating device to capture the formed image. An image output captured by the CCD is analyzed to measure color components of the irradiated surface.