To provide an image pickup device which can attain the effect of depth of field accordant with the situation, the effective description, etc., by decreasing the optimum number of pixels according to the situation and also performing the optimum exposure control in response to decrease of the number of pixels.

A number-of-pixel decrease circuit 108 changes the way of decreasing pixels in accordance with a set 1st image pickup mode (small screen pickup mode) where a prescribed number of pixels are decreased from all pixels of an image pickup device 104 to make up a reduced image.