The object of this invention is to decrease a memory capacity required for a lookup table. To achieve this object, in an image sensing apparatus which causes an image processing section to execute image processing to convert digital image data, which is obtained by A/D-converting the output from an image sensing element, into output image data, the image processing section includes a matrix arithmetic processing section and an N-dimensional (N is a positive integer) lookup table arithmetic processing section. The image processing section causes the matrix arithmetic processing section to process the digital image data before the N-dimensional lookup table arithmetic processing section.