1. A projection display device, comprising: an input module that receives input of an image signal; a discrimination module which discriminates whether the image signal input to the input module is of CG images or of natural images; a color correction module which applies color correction processing for CG images to the image signal input to the input module when the discrimination module determines the image signal is of CG images, or applies color correction processing for natural images to the image signal input to the input module when the discrimination modules determines the image signal is of natural images; and a projection module which generates an optical image based on the image signal applied with the color correction processing by the color correction module, and projects and displays the image on a screen through a projection lens.