An endoscope comprising: a four-color separation prism configured to separate light from an object into three primary colors of light and infrared light; and four image sensors (230, 231, 232, 233) configured for converting optical images of the separated three primary colors of light and an optical image of the separated infrared light into electrical signals; wherein the four-color separation prism includes an infrared separation prism, a blue-color separation prism, a red-color separation prism and a green-color separation prism assembled in a sequence from a light incidence side in the optical axial direction as a first prism, a second prism, a third prism and a fourth prism in the sequence, wherein each of the first, the second and the third prisms (220,221,222) respectively has a light incident surface (220a,221a,222a), a reflective surface (220b,221b,222b) facing the light incident surface, and a light emitting surface (220c,221c,222c), and the fourth prism has a light incident surface and a light emitting surface facing its light incident surface, wherein the four image sensors comprise an infrared image sensor disposed to face the light emitting surface of the infrared separation prism, a blue color image sensor disposed to face the light emitting surface of the blue color separation prism, a red color image sensor disposed to face the light emitting surface of the red color separation prism and a green color image sensor disposed to face the light emitting surface of the green color separation prism, wherein a film reflective to the light to be separated by the first prism and allowing transmission of the light to be separated by the second, third and fourth prisms is formed on the reflective surface of the first prism, wherein a film reflective to the light to be separated by the second prism and allowing transmission of the light to be separated by the third and fourth prisms is formed on the reflective surface of the second prism, wherein a film reflective to the light to be separated by the third prism and allowing transmission of the light to be separated by the fourth prism is formed on the reflective surface of the third prism, characterised in that each of the films (240,241,242) respectively forms the interface area of the prism on which it is formed with the light incident surface of the subsequent prism in the sequence. a four-color separation prism configured to separate light from an object into three primary colors of light and infrared light; and four image sensors (230, 231, 232, 233) configured for converting optical images of the separated three primary colors of light and an optical image of the separated infrared light into electrical signals; wherein the four-color separation prism includes an infrared separation prism, a blue-color separation prism, a red-color separation prism and a green-color separation prism assembled in a sequence from a light incidence side in the optical axial direction as a first prism, a second prism, a third prism and a fourth prism in the sequence, wherein each of the first, the second and the third prisms (220,221,222) respectively has a light incident surface (220a,221a,222a), a reflective surface (220b,221b,222b) facing the light incident surface, and a light emitting surface (220c,221c,222c), and the fourth prism has a light incident surface and a light emitting surface facing its light incident surface, wherein the four image sensors comprise an infrared image sensor disposed to face the light emitting surface of the infrared separation prism, a blue color image sensor disposed to face the light emitting surface of the blue color separation prism, a red color image sensor disposed to face the light emitting surface of the red color separation prism and a green color image sensor disposed to face the light emitting surface of the green color separation prism, wherein a film reflective to the light to be separated by the first prism and allowing transmission of the light to be separated by the second, third and fourth prisms is formed on the reflective surface of the first prism, wherein a film reflective to the light to be separated by the second prism and allowing transmission of the light to be separated by the third and fourth prisms is formed on the reflective surface of the second prism, wherein a film reflective to the light to be separated by the third prism and allowing transmission of the light to be separated by the fourth prism is formed on the reflective surface of the third prism, characterised in that each of the films (240,241,242) respectively forms the interface area of the prism on which it is formed with the light incident surface of the subsequent prism in the sequence.