PURPOSE: To construct an interface between the different kinds of operating systems by a very simple procedure, to enable the interface itself to realize an operation exactly desired by an application programmer and to generate the interface with improved portability and maintenance.

CONSTITUTION: A system call called by an application program operated on a first operating system 1 is analyzed by a system call analysis part 11 and required information is taken out. The extracted information is delivered to a virtual data part 12 by a control part 10 and is held in the virtual data part 12. In the virtual data part 12, the various kinds of the information, when it is considered that the application program is operated on the first operating system 1, are held. Based on the information, a system call conversion part 13 performs a processing corresponding to the system call of the first operating system 1 on a second operating system 2 different from the first operating system 1.