An information processing system comprising: a master node; and a plurality of cluster nodes (2,3,... N) managed by the master node, wherein the information processing system stores a node list (151, 152) having set a transfer sequence for transferring request information sent from the master node to the cluster nodes; wherein the cluster nodes (2, 3,..., N) each include a request transfer unit for accepting the request information sent from the master node or other of the cluster nodes, transferring the request information to yet other of the cluster nodes which are the next transfer destinations according to the node list (151, 152), an transferring the request information to the master node if the next transfer destinations do not exist; wherein the master node includes a request notification unit for sending the request information to one of the cluster nodes according to the node list, and a cluster division unit for dividing the plurality of cluster nodes if a calculated amount of time is larger than a preset threshold value T, wherein the amount of time is calculated based on a time interval after sending the request information from the master node to the one of the cluster nodes until receiving the request information by the master node wherein the request information is sent from the other of the cluster nodes in which the next transfer destinations do not exist; and wherein the cluster division unit divides the plurality of cluster nodes into a first cluster node group positioned under the management of the master node, and a second cluster node group positioned under the management of a predetermined cluster node. a master node; and a plurality of cluster nodes (2,3,... N) managed by the master node, wherein the information processing system stores a node list (151, 152) having set a transfer sequence for transferring request information sent from the master node to the cluster nodes; wherein the cluster nodes (2, 3,..., N) each include a request transfer unit for accepting the request information sent from the master node or other of the cluster nodes, transferring the request information to yet other of the cluster nodes which are the next transfer destinations according to the node list (151, 152), an transferring the request information to the master node if the next transfer destinations do not exist; wherein the master node includes a request notification unit for sending the request information to one of the cluster nodes according to the node list, and a cluster division unit for dividing the plurality of cluster nodes if a calculated amount of time is larger than a preset threshold value T, wherein the amount of time is calculated based on a time interval after sending the request information from the master node to the one of the cluster nodes until receiving the request information by the master node wherein the request information is sent from the other of the cluster nodes in which the next transfer destinations do not exist; and wherein the cluster division unit divides the plurality of cluster nodes into a first cluster node group positioned under the management of the master node, and a second cluster node group positioned under the management of a predetermined cluster node.