A communication control system includes a plurality of nodes 31, and a master device 30 for performing flow control of multihop communication in a network including the plurality of nodes 31. The master device 30 allocates, to each of the nodes, a time obtained by subtracting, from a frame period, a total one frame transmission time of each node, used for first service, as a one frame transmission time used for second service having a priority set lower than that of the first service.