PURPOSE: To utilize the storage area of a main storage device effectively by obtaining the best storage capacity according to execution information in the case that a load module is executed actually.

CONSTITUTION: An execution information gathering means 100 gathers the execution information indicating storage capacity occupied in a main storage device 2 when the load module LM is executed. An execution information storage means 200 stores and holds the execution information that the execution information gathering means 100 every time the load module LM is executed repeatedly. An execution information analyzing means 300 analyzes pieces of execution information held in the execution information storage means 200 to calculate the best storage capacity of a program area AL to be secured in the main storage device 2 so as to execute the load module M. Consequently, the best storage capacity is obtained according to the execution information when the load module is executed actually, so the necessary and sufficient program area is secured to utilize the storage area of the main device effectively.