Disclosed herein are an apparatus and method for setting the allocation rate of a parallel-computing accelerator. The method includes monitoring the utilization rate of the parallel-computing accelerator by an application and setting a start point, at which measurement of utilization data to be used for setting the allocation rate of the parallel-computing accelerator for the application is started, using the result of monitoring the utilization rate; setting an end point, at which the measurement of the utilization data is finished, based on the monitoring result; and setting the allocation rate of the parallel-computing accelerator using the utilization data measured during a time period from the start point to the end point.