A stream data processing system restrains the generation of communication traffic in the case of distributing loads by using a plurality of information processing devices. The global query is divided into a plurality of processes. At every divided process, a local query which includes the corresponding process is generated and each local query is set to a query processing device different from each other. In addition, the stream data is transmitted among a plurality of query processing devices in order so as to execute the local query in each query processing device. At this time, the entire stream data does not transmitted among the query processing devices in order. At least a part of the corresponding stream data is stored in a proxy device. When data received from an information processing device located in immediately before does not include the target data of the local query, the query processing device reads the corresponding data from the proxy device and executes the local query.