Group discussions (hereinafter called "GD") play an important role in academic and corporate activities. This research aims to evaluate talking skills and listening skills which are the basic skills in GD using acceleration sensors. In the experiments acceleration sensors were mounted on participant’s chest, head and both arms and gathered sensed data during the discussion as well as video and audio data. We analyzed scenes of GD in terms of the skills based on behaviors of participants using measured values of accelerometers. The case studies suggest that the values of the acceleration of the arm increase while the participants were speaking ambitiously. It was also found that the values of acceleration decrease as the motivation of utterance decreases.