To obtain a method for converting only a common code to be practically accessed by application at the time of execution into an execution code for debugging by dynamically converting a 1st code block during the execution of 1st application to prepare a converted code block and arranging a debugging processing code in the converted code block.

The 1st application for utilizing the 1st code block in a shared library 46 held at a state to be utilized by application 41 included in a computer system is dynamically converted during the period of its debugging processing to prepare a converted code 101. The dynamic conversion includes the conversion of the 1st code block to be used in the shared library 46 and the preparation of the converted code block. The converted code block is included in the dynamically converted application code. Then a debugging processing code such as a brake instruction is added to the converted code 101.