In group discussions, facilitation is often employed to encourage equal participation among members. However, excessively directive methods disrupt the natural flow of discussion, whereas excessively passive methods fail to ensure equal participation. In this paper, we introduce “moderate facilitation”, an approach that aims to balance equal participation with the natural flow of discussion. To realize this, we use small tabletop robots that promote turn-taking by physically approaching participants. We evaluated this system in a group discussion task under three experimental conditions: multiple-robot, one-robot, and no-robot conditions. The results indicated that the robot-assisted (multiple-robot, one-robot) conditions, as shown by reduced variance in speaking time among participants, contributed to more equal participation without disrupting the natural flow of discussion.