PURPOSE: To configurate most of the device by digital components by applying 1st gamma correction to an output of a solid-state image pickup means of an image pickup device whose components are arranged on a same optical axis, A/D-converting the result and applying required processing including a 2nd gamma correction to the A/D-converted signal so as to employ A/D converter means with low bit accuracy.

CONSTITUTION: An image pickup signal from an image pickup device comprising an objective lens 1, an optical LPF 2, an infrared ray cut filter 3, a color filter 4 and a solid-state image pickup means 5 being an optoelectric conversion means arranged on a same optical axis is converted into a digital signal by an A/D converter 8 via a buffer device 6 and a 1st stage gamma correction means 7 with a fixed characteristic. Then the digital signal is inputted to a camera process means 11 via a 2nd stage gamma correction circuit 9 with a variable characteristic controlled in response to the detected luminous quantity and an AGC 10. When an output voltage V1 of the device 6 proportional to an incident light is selected to have a relation of V1>V2, where V2 is a maximum output voltage of a means 7 compressing the input voltage, bit accuracy of the means 8 is kept low and most of the circuits is configurated by a digital component through the use of the A/D converter means with a low bit accuracy.