1. An embroidery data creation apparatus for creating embroidery data required to sew embroidery that represents an image with a zigzag stitch, comprising: an image storage device that stores the image made up of a plurality of pixels, each of the pixels having a color value; a division device that divides the stored image device into divided regions, each of which is a predetermined region through which one zigzag stitch passes; a calculation device that calculates a reference swing position that provides a reference for swinging the zigzag stitch passing through each of the divided regions and a maximum value of a swing width of the zigzag stitch for each of the divided regions, based on the color values of the pixels in each of the divided regions; and an embroidery data creation device that creates the embroidery data based on the calculated reference swing position and the calculated maximum value of the swing width.