PURPOSE: To execute exposure control with high accuracy by a simple circuit, by processing the storage and operation required for the exposure control by a digital circuit, and processing the expanding of a real time of an exposed value by an analog circuit.

CONSTITUTION: From an operational amplifier 2, logarithmically compressed analog voltage corresponding to luminance of an object to be photograped is outputted. This analog voltage is converted to a digital value by an A/D converter 18 consisting of a D/A converter 16 and an operational amplifier 17, and is supplied to a CPU20. The CPU20 calculates a digital value corresponding to an exposure time in accordance with the supplied digital value. Subsequently, this digital value is converted to analog voltage by the D/A converter 16, and after that, is logarithmically expanded by a transistor 26. In this way, since each characteristic of both digital control and analog control is utilized, exposure control with high accuracy can be executed by a simple circuit.