1. An execution code generating method for adding a code to an execution code to be executed on a computer which includes a CPU having a power consumption reduction function, a cache memory, and a main memory, the code enabling the power consumption reduction function of the CPU, the method comprising the steps of: reading a code which is preset and analyzing an amount of operation of the CPU and an access amount with respect to the cache memory based on the code; obtaining an execution rate of the CPU and an access rate with respect to the cache memory based on the amount of operation and the access amount; determining an area in which the access rate with respect to the cache memory is higher than the execution rate of the CPU, based on the code; adding a code for enabling the power consumption reduction function to the area in which the access rate with respect to the cache memory is higher than the execution rate of the CPU; and generating an execution code executable on the computer, based on the code.