This article study how interviewees accomplish "showing their state of knowledge" and "participating" in group interview settings. Group interview's topic was" science and technology", especially "regenerative medicine". Interviewees were non-expert person of regenerative medicine, and were not acquainted with each other. In this situation, interviewee's interactional problem is how describe own state of knowledge. Interviewee's descriptions are conducted by co-participants to see what he/she is doing by talking in that way. In this article, we describe interviewee's action over their state of knowledge of regenerative medicine, and based on the results of the description, elucidate their "method" of participation in interaction. In light of the above, we discuss the contribution of this article's description for science communication colleagues.