To provide a computer performance evaluating device without needing that a simulation instruction string is especially prepared from application and read out.

A simulator part 2 executes simulation for instruction execution in a virtual computer under the control of a control part 4 and finds out information such as the using frequency and using time of respective constitutional elements of the computer and a performance evaluating part 3 evaluates the performance of the computer based on the information. A load module analyzing part 1 is connected to the input part of the simulator part 2. The analyzing part 1 reads out an application load module 5, executes analysis based on a load module format to prepare an instruction, calculates a memory address in the virtual computer for loading the instruction, and successively outputs the obtained instruction and its address to the simulator part 2.