Image encoding device encoding an image by performing sequential processing, method for encoding image, and computer-readable storage medium storing image encoding program

An image encoding device that encodes an image by performing sequential processing in units of a certain size, the image encoding device includes, a variable-length coding unit that performs variable-length coding on data to be encoded having the certain size in the image; an estimating unit that estimates the number of codes at a time after the variable-length coding using the data to be encoded at a time before the variable-length coding is performed by the variable-length coding unit; and a slice controlling unit that controls division of the image into slices on the basis of a cumulative value of the estimated number of codes.