A load balancing system (1) according to the present disclosure includes a processing unit (10-1), a processing unit (10-2) that processes a processing result of the processing unit (10-1), a processing unit (10-3) that processes a processing result of the processing unit (10-2), a resource management unit (20-1), a resource management unit (20-2), and a resource management unit (20-3). When the resource management unit (20-2) detects an occurrence of an overload in the processing unit (10-2), the resource management unit (20-2) starts to add a resource of the processing unit (10-2), the resource management unit (20-3) starts to add a resource of the processing unit (10-3), and the resource management unit (20-1) starts to suppress throughput of the processing unit (10-1). When it is completed to add resources of the processing units (10-2) and (10-3), the resource management unit (20-1) cancels suppression of throughput of the processing unit (10-1).