PURPOSE: To perform the correct debugging even to a source program produced in a precompiler language with the use of the source program symbolic information by producing a corresponding table between the source program symbolic information and the produced source program symbolic information.

CONSTITUTION: A corresponding table 12 is produced between the source program symbolic information and the produced source program symbolic information. Simultaneously a schema 13 of a produced source program 11 is produced at compiling based on the produced source program symbolic information. When a program 6 to be debugged is carried out, the row number and the label of a source program 10 incorporated in the debug instruction information 16 are converted into the produced row number and the produced label of the program 11 based on the table 12. Then a designated debugging operation is carried out based on the contents obtained after the conversion and the schema 13. Thus even the program 10 produced in a precompiler language can be correctly debugged with the use of the source program symbolic information.