Due to the impact of the COVD-19 online communication using Zoom, Microsoft Teams, Cisco Webex, etc. has become common in various situations such as business and education. From the viewpoint of privacy protection, security, and communication load reduction, there are many scenes where communication is performed with the video turned off. When we compared the patterns of conflict of opinion in dialogue, the time it took to build consensus, and the quality of decision-making, we found that with “video off”, people began to avoid conflict of opinion caused by the diversity of members, and it took longer to reach consensus. As a result, it was concluded that the quality of decision-making deteriorated. In the future, we hope that dissemination of the results of this research will lead to smooth dialogue in situations where online communication is required, such as business and education, leading to improved productivity and the creation of innovation.