In a processing system 101, a first processing device 111 obtains first characteristics information indicating characteristics of users in a first environment, divides the users into first clusters according to the first characteristics information, and transmits, to a second processing device 121, representation information representing characteristics of users belonging to each of the first clusters using a centroid vector based on the first characteristics information of the cluster. The second processing device 121 obtains second characteristics information indicating characteristics of the users in a second environment, and divides the users into second clusters according to the representation information and the second characteristics information. The present invention allows for dividing the users into clusters more accurately, although the second processing device 121 need not use the first characteristics information and the first processing device 111 need not use the second characteristics information.