For multi-target tracking, we realize the increase in number of simultaneously trackable objects and tracking stability by improving the way of communication proposed in [1] so that agents exchange all detected information with each other without increasing network traffic as follows: (1) an agent that provides information of observed objects for multiple agencies (an agency is a group of agents that track the same target) and (2) a vacant-agency that receives information of its target from agents tracking other objects. Categories and Subject Descriptors I.4.8 [Image Processing and Computer Vision]: Scene Analysis—Tracking General Terms Design Keywords Target tracking, Tracking by multiple active-cameras, Realtime communication