The invention provides a stream data control module which can easily achieve a function expansion of a digital device and can simply, safely and inexpensively realize the recording and reproducing of stream data for a storage device. A stream data control module includes a stream I/F unit exclusively inputting and outputting stream data, a non-stream I/F unit inputting and outputting non-stream data, a device I/F unit providing an interface to data storage means, and a control unit executing a transfer process of the stream data in response to a recording command and a reproducing command given from host means. The control unit has a stream arrangement management unit managing a storing position of the stream data in the data storage means, a scheduling unit controlling a transfer order of the stream data and the non-stream data, and a command processing unit interpreting various commands given from the host means.