1. A threshold value data setting device which sets threshold value data for creating a binary image signal representing the shape and arrangement of respective pixels constituting an image based on a continuous tone image signal, the threshold value data setting device comprising: a threshold value candidate acquisition unit which acquires dot information relating to the shape and arrangement of the respective dots linked to the continuous tone image signal and acquires a plurality of pieces of threshold value data matching the dot information as respective threshold value candidates; a response characteristics acquisition unit which acquires a change in dot shape occurring in an image forming process from the creation of the binary image signal to the formation of the image as response characteristics in a spatial frequency domain; a simulated image creation unit which applies the response characteristics acquired by the response characteristics acquisition unit to create a simulated image signal in which the change in dot shape is reproduced in a simulated manner; a quantitative value calculation unit which calculates an evaluation value obtained by executing predetermined evaluation processing for the simulated image signal created by the simulated image creation unit as a quantitative value indicating the degree of image quality; and a threshold value data determination unit which applies the respective threshold value candidates acquired by the threshold value candidate acquisition unit and determines threshold value data to be set from among the respective threshold value candidates by a comparison and/or evaluation based on the quantitative values calculated by the quantitative value calculation unit.