To miniaturize an image signal processor and to reduce costs even while outputting images in suitable colors / brightness to each of a plurality of display media.

The image signal processor comprises: a parameter adjustment means of one system which is capable of adjusting the parameter of image signals to be outputted to each of a plurality of types of external devices; and at least one image signal holding means provided corresponding to at least each of the external devices excluding one external devices and capable of holding and outputting the image signals whose parameter is adjusted for the corresponding external devices, respectively.