An endoscope includes: a light source for emitting white light or narrow band light； a color filter having a first filter for passing light in WLI and NBI, a second filter for passing light in WLI, a third filter for passing light in NBI； and a demosaicing processor that: generates a color image signal based on a luminance component in WLI under the white light； and performs interpolation for a pixel of a luminance component in WLI at a position of a pixel corresponding to the first filter using a pixel corresponding to the second filter under the narrow band light, and then, performs interpolation for a pixel of a luminance component in NBI at the position of the pixel corresponding to the first filter based on a pixel corresponding to the first filter and the pixel of the luminance component in WLI, thereby generating a color image signal.
