Disclosed is a moving picture encoding/decoding apparatus and method for processing of a moving picture, which is divided in units of slices. The encoding method includes the steps of: dividing a moving picture in units of slices when the moving picture is received; determining an encoding order of moving pictures divided in units of slices; and generating a bitstream by encoding moving pictures, which are divided in units of slices, according to a corresponding order when the encoding order has been determined.