To provide an exposure control device of a digital camera which can realize rapidly optimum exposure control with simple constitution, without changing the gradation feature.

An output signal of an imaging element 3 is divided into m×n. A target window and a desired value are obtained from the luminance distribution of an object and luminance signal data of each of the regions of the whole image, a large window of the central image and a small window of the central image. The luminance level of the target window is controlled to be equal to the desired value by an exposure control means with an electronic shutter of the imaging element 3.