This study examines a function of fillers as maintaining the speaker′s right to speak in conversation. We analyze the fillers appeared in the conversational data during the cooperative task in which 28 pairs of participants are engaged. In particular, it is investigated that how the hearer deals with the speaker′s fillers. The study reveals that while over 80‰ of fillers at the beginning of sentence and over 90‰ of fillers during the sentence are not interrupted by the hearer, there are some cases where the hearer does take the turn after the speaker′s fillers. Those cases seem to depend on the expression types of the fillers. The further analysis of the conversational sequences of the cases suggests that some of those hearer′s interruptions are inevitable or not improper. Even some “failure” cases, the hearer sees the filler as the indication of more talk to come from the speaker.