An imaging apparatus includes an image pickup device having a two-dimensionally arrayed pixel structure, an A/D converter which converts analog signals from the respective pixels into digital data signals, and a DSP 30 which performs signal processing for the data signals. The DSP 30 includes an image data storage 32 which stores the data signals in units of data signal sequences corresponding to pixel lines, a mask processor 34 which sets an integer n not less than 2 as a dilation coefficient and performs mask processing to dilate image components in the image data to n×n, and a data storing controller 37 which sets n calculation memory regions in which n data signal sequences corresponding to n pixel lines are stored, in the storage 32, according to the dilation coefficient n. Thereby, an imaging apparatus capable of acquiring an image with excellent visibility even under conditions of a low illuminance, etc., is realized.