1. A coding artifacts removing method of removing coding artifacts from pixels of a processed edge in an image signal, said method comprising: determining, based on at least pixel values of adjacent pixels, a target pixel from which coding artifacts are to be removed for the processed edge, the adjacent pixels being adjacent to the processed edge; and removing the coding artifacts from the determined target pixel, wherein said determining and said removing are performed for each processing unit including at least one of pixels included in the image signal, pixel values of pixels which are included in a processed processing unit and from which the coding artifacts are not removed are stored in a storage unit, the pixels which are included in the processed processing unit include at least one of the adjacent pixels, and in said determining, at least one of the pixel values of the adjacent pixels which are included in the processed processing unit is read from the storage unit, and the target pixel is determined based on the at least one read pixel value.