1. A method for controlling operating speed of a processor which allows said operating speed to be varied depending on an execution module, comprising the steps of: registering execution modules in association with operating speed attribute data by analyzing code containing operating speed of each of the execution modules as attribute data; grouping the registered execution modules by operating speed based on the associated operating speed attribute data, and creating a file header containing attributes of each group; upon loading an executable file containing said file header into memory at the time of execution, associating operating speed attribute data with an address range of said loading for each execution module in said executable file; and controlling the operating speed of the processor executing an execution module according to the operating speed attribute data associated with the address of said execution module when said module is executed.