PURPOSE: To reduce a sense of incongruity in conversation due to the delay of voice and video signals by interposing a delay device having a specific delay amount between a voice microphone and a voice indicator.

CONSTITUTION: A delay device A103 takes the lipsync between the voice and video signals by correcting the difference of delay amount of the voice signal encoded by a voice encoding device 102 and that of the video signal encoded by a video encoding device 105. A delay device B108 takes the lipsync between the voice signal decoded by a voice decoding device 109 and the video signal decoded by a video decoding device 111. The voice inputted from a voice microphone 101 is inputted to the voice encoding device 102 and displayed through a delay device C113 by a voice indicator 114. The delay amount of the delay device c113 corresponds to the sum of delay amount between delay devices A103 and B108. Thus, it is displayed on a voice indicator 114 in close timing that the voice inputted through the voice microphone 101 reaches the communication party through a communication line 115.