PURPOSE: To improve the utilization efficiency for a memory by designating compression at the time of loading only for the execution of a program and eliminating space unnecessary for the execution of the comment and the program out of the program.

CONSTITUTION: In the case of the compression of the program, when the program is converted into an ASCII code, the elimination of the comment in the program is performed at first, and the conversion into the internal code is performed, then the elimination of the space unnecessary for the execution of the program is performed to store it to the text area of a main storage device. On the other hand, when the program is converted into the internal code, the eliminated of the unnecessary space is performed to store it in the text area of the main storage device after the elimination of the comment. Thus, the text area of the main storage device can be saved and the money utilization efficiency can be improved by designating the compression when the program is loaded so as to be only executed.