We have been attempting to realize simultaneous machine interpretation. However, determining the interpreting utterance timing is as difficult as determining translation units. This remains a major concern for the development of such a speech translation system. It is also crucial for the system’s users that the speech generated by the system is clear and easy to listen to. In this paper, we focus attention on the pauses that partly characterize simultaneous interpreters’ utterances. We attempt to analyze the results of an experiment conducted using 31 subjects on the relationship between listener-friendliness and the length of pauses in speech, using the CIAIR simultaneous interpretation database as the data source. The results generated some knowledge about listener impressions of simultaneous interpretation, which will be helpful for realizing simultaneous machine interpretation.