PURPOSE: To suppress the cooling capability required for a parallel computer system to reduce the operation cost of the whole of the system by performing the selection processing of a specific processor to be the schedule object of a new process so as to uniformize the operation temperatures of respective processors.

CONSTITUTION: A process schedule processing part 13 is started at each time of the occurrence of a process assignment request to processors P11 to Pmn constituting the system and obtains a threshold of the operation temperature of each processor in each of nodes N1 to Nn at first. A management table 12 is referred to find the node satisfying the condition that processors, which have minimum values of operation temperatures lower than thresholds of operation temperatures and can be operated, exist. Thereafter, the processor whose operation temperature is minimum is found, and the process is assigned to this processor. Since the process is assigned to the processor which has the minimum operation temperature and can be operated in this manner, unevenness of the temperature rise between processors constituting the system is prevented.