Infrared light emitted by a fluorescent material is weak. When an infrared image obtained by this fluorescent material is superposed and displayed on a visible-light image, the infrared image is made clear. A signal <；IR>； of an IR pixel having selective sensitivity to infrared light is subtracted from RGB pixel signals <；R>；, <；B>；, and <；G>； of a solid-state image sensor by adders (20), and signals R0, G0, and B0 that correspond to the R, G, and B components of incident light within <；R>；, <；G>；, and <；B>； are separated and extracted. <；IR>； is multiplied by each of the gains &kgr；R, &kgr；G, and &kgr；B to enhance the IR component by multipliers (22), and each is synthesized with R0, G0, and B0 by adders (24). &kgr；R, &kgr；G, and &kgr；B are set so that the infrared image displayed on the visible-light image by the synthesized IR component is enhanced and displayed in a hue that can be distinguished from the color white or another visible-light image.
