PURPOSE: To curtail the necessary secondary storage capacity and to simplify the program management by sharing an intermediate code generated by a compiler even between computers having no interchangeability of an object program, and converting it to an object program to each computer at the time of execution and executing it.

CONSTITUTION: A source program 1 is converted to an intermediate code 5 by the first half processing part 2 of a compiler, and the intermediate code 5 is stored in a secondary storage device 15 connected to a computer 13. When the execution requirement of a program is generated on a computer 11 or 12, a computer 13 fetches the intermediate code 5 from the secondary storage device 16, and transfers it to the computer 11 or 12 through a transmission line 10. A mechanical instruction generating program 7a or 7b on the computer 11 or 12 converts the transferred intermediate code 5 to the mechanical instruc tion code of the computer 11 or 12, and subsequently, the computer 11 or 12 executes the converted mechanical instruction. In such a manner, the secondary storage quantity required for storing an object program to respective computers 11, 12 is curtailed, and also, the program management including a version man agement is simplified.