An endoscope includes a solid image-pickup device having an image area and an optical black area for performing photoelectric conversion and including a function of varying an amplification ratio, and a first signal clamp circuit clamps the analog output signal that is outputted from the solid image-pickup device to adjust into an input range of the analog signal processing circuit with an analog reference signal which is unaffected by a defective pixel in the optical black area. The clamped signal is processed to extract signal components which are photoelectrically converted by the analog signal processing circuit by the image area. The output signal from the analog signal processing circuit clamps the signal in the optical black area by using output signals of at least the number of pixels larger than the number of pixels in a horizontal direction in the optical black area by the second signal clamp circuit.
