This research examines the use of the ellipsis in 30 telephone conversations and shows the reason for the use of the ellipsis in aspects of functionality in the area of study of Korean and Japanese. It also demonstrates if the supplementary of utterance has which type of format at each functionality and if there are the format of the supplementary of utterance repeated. The results below are described in detail 1. The functionality of the ellipsis at the end of sentence in both languages (1) Demanding Behavior: request, recommendation, proposition, (2) Demanding Information: question, confirmation request, (3) Providing Information: self-information, the third person, reason, conveying a story to the others, and (4) Expressing will: revision/ evaluation, self-behavior in future, compliance/support, apology, greeting. 2. The format of the supplementary of utterance of the ellipsis at the end of sentence in both languages. In regard of the format of the supplementary of utterance, Korean has the connection formats, which are「-고」「-ㄴ데」「-니까」and so on, Japanese has「-けど」「-から」「て」「って」and the like. The study shows that formats repeated are existed in the ellipsis at the end of the sentences in both languages.