This article reports field research on project meetings for developing an exhibition at a science museum. These meetings were held in consecutive weeks over half a year. The project team, consisting of members with diverse professions, collaborated on construct- ing a novel exhibition. In the process of construction, problems discovered by a team member often could not be solved individually. Therefore, members had to launch collaborative problem-solving by relying upon interactional procedures, wherein one member described a problem to the others. One of the procedures, which this article examines, involves the usage of concern-introducing expressions, “kini-naru/suru-no- wa/ga”(what the topic of concern is), appearing in approximately 30 meetings. These expressions are examined in terms of their linguistic features. An analysis of sequential relation of an utterance including this expression to the following utterances illustrates that these expressions play a role for requesting other members to cope with solving the problems presented. Finally, factors behind the use of concern-introducing expressions are discussed in the light of members’professions and function of emotion.