Although there are a lot of opportunities to have a multi-party conversation such as decisionmaking meeting and brainstorming, we do not always have a good communication. In multi-party conversation, it sometimes ends up as one-way conversation because of someone's too much speaking, and people cannot understand a less-speaking person's thought. Considering the situations where a balanced participation is desirable, the amount of speaking time should be well controlled. We propose a co-located meeting support system called ScoringTalk that activates conversation by visualizing conversation state in real-time, providing scores based on the amount of conversation, and facilitating participant's behavior such as speaking, listening, and changing a conversation partner to make a balanced conversation. In ScoringTalk, each participant has a tablet with dual camera, and it works as both sensor and display. Tablets are commonly used in social meetings, therefore, there are no need to prepare projectors and microphones. The evaluation result showed that our system measured conversation, provided the visualization of conversation, scores, and facilitation, and increased the balance of participation while keeping the amount of speaking time.