An image processing device includes a processor configured to perform: acquiring target image data representing a target image; and generating binary image data representing the letter in the target image by using the target image data. The generating of the binary image data comprises: identifying a background color value representing color of background of the target image; identifying a letter color value representing color of the letter in the target image; acquiring a difference between the background color value and the letter color value, the difference including a plurality of component differences; selecting one specific component image data corresponding to a specific component from among the plurality of components, the specific component corresponding to a maximum component difference among the plurality of component differences; and performing a binarizing process on the selected one specific component image data to generate one binary image data.