1. A line-direction deciding device comprising: image storing means for storing an input image; character-element extracting means for extracting character elements from the image stored in the image storing means; character-element distance calculating means or character-element density calculating means for determining the density of character elements in each of plurality of predetermined directions; and line-direction deciding means for detecting a direction in which character elements are most densely distributed, and deciding a character line direction in the image as the detected direction in which the character elements densely distributed.