PURPOSE: To improve the productivity of software, by providing a common interface means accessible in common from a compiler means and a syntax checker means to a common syntax analysis section to make the extension and maintenance of the language system easy.

CONSTITUTION: A syntax checker 17 (load unit 1) and a compiler 18 (load unit 2) are connected to a common structure analysis section 3 checking the syntax of a source program 5 to constitute the syntax check system for a high-class language. The analysis section 3 is provided with a common interface section 15 and a syntax analysis section 16, and after the user edits and forms a program by using a TSS terminal 1, the result is inputted to a control section 2 of the checker 17. The source program inputted is converted into a common interface of the analysis section 3 at the control section 2 and inputted to an analysis section 16 via an interface section 15. Further, the syntax is checked at the analysis section 16 and classified into the required information for the checker section 17 and the compiler 18 at the interface section 15, and supplied to each.