Abstract: A batch job multiplex processing method which solves the problem that a system which performs multiplex processing including parallel processing on plural nodes cannot cope with a sudden increase in the volume of data to be batch-processed using a predetermined value of multiplicity, for example, in securities trading in which the number of transactions may suddenly increase on a particular day. The method dynamically determines the value of multiplicity of processing including parallel processing in execution of a batch job on plural nodes. More specifically, in the method, multiplicity is determined depending on the node status (node performance and workload) and the status of an input file for the batch job.