在本研究中是以「日語談話資料庫」中「自由討話」的「Dakara」的意思和機能為焦點，由它的使用情況來觀察溝通的禮貌策略。資料的數量是母語場面10個會話，發話者都是介於20～40歲，初次見面的會話。其結果如下:在此次的談話資料中觀察到有1.「聽我說喔」的暗號，2.話題管理，3.「理解一下喔」的明示，4.說明的預告等機能。另外，「理解一下喔」的明示和說明的預告是「對他人態度的表明」，屬於希望對方能接受主體所傳達的考慮方式和態度的積極性禮貌的機能。「聽我說喔」的暗號則實現了「參加行為的管理」的功能，是讓對方有面子，顧慮對方面子，相當於重視對方消極性的面子。再者，話題管理也實現了「參加行為的管理」的功能，相當於橫跨積極性以及消極性的禮貌。

This research focus on the meaning and function of 「Dakara」 in 「free dialogue」 in CSJ to observe politeness strategy in communication by its usage. The quantity of data is 10 native speakers' conversations go to 10 minutes, and they met each other for the first time. The age of speakers is between 20~40 years old. We can observe the following results in this conversation data; The signal of 「kiitene」, 2. Topics management, 3. The express of 「wakatteyo」, 4. The previous notice of explanation. The express of 「wakatteyo」 and the previous notice of explanation is a 「expression toward others」. It means speakers want listeners accept his own thoughts and attitude, and let listeners know the attempt of appeal. This shows the function related to positive politeness. Moreover, the signal of 「kiitene」 fulfill the 「management of joining acting」, to preserve appearances and consider the face of listeners, this makes a great deal of 「negative face」. 「Topics management」 also fulfill the 「management of joining acting」, we can say it straddles two areas between positive politeness and negative politeness.