An endoscope system comprising an imaging device, an input block, and a signal processing block, is provided. The imaging device has first, second, third, and fourth pixels. The first, second, third, and fourth pixels are covered with first, second, third, and fourth color filters, respectively. The first, second, third, and fourth color filters can be penetrated by first, second, third, and fourth light components, respectively. The first light component reaches a depth, predetermined according to the location of an object, under an organ. The second light component belongs to an identified color of the first light component. Further, a band of the second light component is different from that of the first light component. The input block detects a users input for selecting one of a number of predetermined display modes. The signal processing block carries out edge enhancement processing for a pixel signal generated by the first pixel. The edge enhancement processing for the pixel signal is carried out when a narrow band image display mode is selected.
