PURPOSE: To improve measurement precision by measuring the starting time and ending time of routine execution from the 1st and 2nd prescribed check routines, and then applying them to a prescribed arithmetic expression and thus calculating the execution time of measured instructions.

CONSTITUTION: The 1st and 2nd check routines consisting of instructions whose execution time is to be measured, prescribed environmental setting instructions, and branch instructions for repeatedly excuting those instructions at a prescribed frequency N are set. Then, the starting times Ts1 and Ts2 and ending times Te1 and Te2 of the routine execution are measured. An arithmetic expression[(Te1-Ts1)-(Te2-Ts2)]/N is used to find the execution time of the measured instructions. Thus, the execution time of instructions executed in a computer, etc., is measured with high precision.