Abstract: In a system in which a plurality of programs each enter an execution wait state at a given time point and they are sequentially executed in the order of their cutoff times, the execution completion time point of a program undergoing estimation of execution completion thereof is estimated based upon the average value of intervals representing the lengths of time to elapse before an execution request for a program present in the system arrives, the average value of the execution times of the individual programs in the system, the lengths of time to elapse between the execution request arrival time points and the cutoff times, the execution time of the program undergoing estimation of execution completion thereof and the execution request arrival time point of the program undergoing estimation of the execution completion thereof, thus achieving a structure that enables estimation of the response time of a program without necessitating a lengthy process such as an actual or simulated execution of the program.