A projection display device according to the invention includes a separating unit that assigns X separation information for identifying a type of an image to each pixel by using a characteristic amount of the input image, a luminance detecting unit that detects a luminance of a screen, a first determining unit that determines a first target region indicating a region on which halftone processing of converting the number of gradations is performed on the input image by using the X separation information, and a halftone processing unit that executes the halftone processing that varies depending on the luminance on the first target region.