There is provided a parallel computer system for performing barrier synchronization using a master node and a plurality of worker nodes based on the time to allow for an adaptive setting of the synchronization time. When a task process in a certain worker node has not been completed by a worker determination time, the particular worker node performs a communication to indicate that the process has not been completed, to a master node. When the communication has been received by a master determination time, the master node performs a communication to indicate that the process time is extended by a correction process time, in order to adjust and extend the synchronization time. In this way, it is possible to reduce the synchronization overhead associated with the execution of an application with a relatively large variation in the process time from a synchronization point to the next synchronization point.