Discussion quality assessment tasks have recently attracted significant attention in natural language processing. However, there have been few studies on challenging such tasks, with a focus on synchronous discussions. In this study, we annotate quality scores to each discussion in an existing multi-modal multi-party discussion corpus. Furthermore, we propose some quality assessment methods with multi-modal inputs. As the results show, attention-based long short-term memory (LSTM) with multi-modal inputs produces the best performance for the "Effectiveness" criterion whereas text information has an important role in the "Reasonableness.