1. A coding artifacts removing method of removing coding artifacts in a first processed edge and a second processed edge that are processed edges in an image signal and are in different directions, said method comprising: determining, based on at least pixel values of first adjacent pixels, a first target pixel from which coding artifacts are to be removed for the first processed edge, the first adjacent pixels being adjacent to the first processed edge; removing coding artifacts from the determined first target pixel; determining, based on at least pixel values of second adjacent pixels, a second target pixel from which coding artifacts are to be removed for the second processed edge, the second adjacent pixels being adjacent to the second processed edge; and removing coding artifacts from the determined second target pixel, wherein in said determining of a second target pixel, the second target pixel is determined based on pixel values of the second adjacent pixels from which the coding artifacts are not removed in said removing from the determined first target pixel.