A color separation apparatus comprising: a target value acquisition device (102, 104) which acquires target values of each colors to be reproduced in a printer from continuous-tone image data when the printer creates a piece of binary image data which is necessary for forming dots of an image for each of color materials and shows shape and arrangement of dots constituting an image for each of color materials; a dot threshold data acquisition device (112, 114) which acquires dot threshold data including information on a threshold for each of the dots for converting the continuous-tone image data into the piece of binary image data for each of the color materials; a print profile acquisition device (106, 108) which acquires a print profile showing correspondence between a device signal value in the printer and a value of a color system; a device signal value candidate calculation device calculates candidates of the device signal value for reproducing colors corresponding to the target values by the printer, on the basis of the target values of colors acquired by the target value acquisition device and the print profile; characterized by further comprising a simulation device which applies binary coded processing to the candidates of the device signal values by using the dot threshold data to create the piece of binary image data for each of color materials for each of the candidates, and simulates an image formed by the printer on a printed matter by superimposing pieces of binary image data for each of the color materials, the simulation device performing on-plate dot shape estimation processing for estimating shape and arrangement of dots to be formed on a printing plate of the printer and on-printed-matter dot shape estimation processing for estimating shape and arrangement of dots to be formed on the printed matter by the printing plate; a color evaluation value holding device which holds a color evaluation value showing a color difference between a device signal value and a color corresponding to the target value for each of the candidates of the device signal values; an image quality evaluation value calculation device which calculates an image quality evaluation value for each of the candidates of the device signal values on the basis of a result of simulation of the image to be formed on the printed matter; and a device signal value determination device which determines a device signal value for reproducing colors corresponding to the target values by the printer, from among the candidates of the device signal value on the basis of the color evaluation value and the image quality evaluation value. a target value acquisition device (102, 104) which acquires target values of each colors to be reproduced in a printer from continuous-tone image data when the printer creates a piece of binary image data which is necessary for forming dots of an image for each of color materials and shows shape and arrangement of dots constituting an image for each of color materials; a dot threshold data acquisition device (112, 114) which acquires dot threshold data including information on a threshold for each of the dots for converting the continuous-tone image data into the piece of binary image data for each of the color materials; a print profile acquisition device (106, 108) which acquires a print profile showing correspondence between a device signal value in the printer and a value of a color system; a device signal value candidate calculation device calculates candidates of the device signal value for reproducing colors corresponding to the target values by the printer, on the basis of the target values of colors acquired by the target value acquisition device and the print profile; characterized by further comprising a simulation device which applies binary coded processing to the candidates of the device signal values by using the dot threshold data to create the piece of binary image data for each of color materials for each of the candidates, and simulates an image formed by the printer on a printed matter by superimposing pieces of binary image data for each of the color materials, the simulation device performing on-plate dot shape estimation processing for estimating shape and arrangement of dots to be formed on a printing plate of the printer and on-printed-matter dot shape estimation processing for estimating shape and arrangement of dots to be formed on the printed matter by the printing plate; a color evaluation value holding device which holds a color evaluation value showing a color difference between a device signal value and a color corresponding to the target value for each of the candidates of the device signal values; an image quality evaluation value calculation device which calculates an image quality evaluation value for each of the candidates of the device signal values on the basis of a result of simulation of the image to be formed on the printed matter; and a device signal value determination device which determines a device signal value for reproducing colors corresponding to the target values by the printer, from among the candidates of the device signal value on the basis of the color evaluation value and the image quality evaluation value.