PURPOSE: To improve the availability of a common memory, to surely attain a transmission band, and to attain the accurate synchronization between the voices and the images.

CONSTITUTION: A writing pointer 22 of a voice output controller 21 adds the time stamps to the voice data received by a memory 18A for each block in a voice output module. When each these blocks arrives at a prescribed position, a reading pointer 23 reads the time stamp of the block and reports the input time point of the voice data to a voice data output timing control means 24. An image output module also includes the writing and reading pointers which report the input time point of the image data to the means 24. The means 24 controls the output timing of the voice data so that the difference between the input time points of both data set within a prescribed range.