A communication control system includes a plurality of layer 2 switches (SWs); and a communication control device that controls communication of the SWs. Each SW includes one or more queues that each have a variable queue length for accumulating input frames, and a transmission unit that has a shaping function of transmitting the frames accumulated in the queues to a desired destination at a desired rate. The communication control device includes a correction processing unit that acquires an amount of discarded data generated in each queue of the SW, and multiplies the acquired amount of discarded data by a correction coefficient weighted by the cumulative number of times of discarding occurrences for which the amount of discarded data is not 0 to obtain a corrected amount of discarded data; and an adjustment processing unit that determines adjustment values for the queue length of each queue and shaping rate of the SW based on the corrected amount of discarded data, and notifies each SW of the adjustment values.