A disk apparatus for reproducing in a preliminary determined order digital video data recorded in a plurality of areas of an optical disk at different positions with respect to the radial position of the optical disk in a reproduction mode by an optical head. The reproduced video data is stored in a buffer memory and encoded by an MPEG decoder. The amount of digital video data corresponding to the access time for accessing the recording areas of the optical disk are reproduced from the optical disk at a speed higher than the bit rate at which the video data is input or output and stored in the buffer memory. The digital video data are continuously read out and reproduced from the buffer memory when the optical head is in the recording areas and accesses between the recording areas.