The present invention is a decoding apparatus for decoding an encoded video signal capable of displaying a secondary video synchronously with a primary video. The decoding apparatus includes: an auxiliary information analyzing part that analyzes auxiliary information including display auxiliary information about a display position and/or a display size of the secondary video, and applied time information by which the display auxiliary information is applied; a reference time counter that indicates a reference time at which a video is decoded and displayed; a comparing part that compares the applied time information with the reference time counter; a display screen forming part that uses a primary video and a secondary video to form a display screen; and a control part that controls the display screen forming part, wherein the control part controls the display position and/or the display size of the secondary video by affording a command to the display screen forming part using the display auxiliary information, based on an output result of the comparing part.