PURPOSE: To improve debugging efficiency by inputting a module name and an in-module relative address from an external input mechanism and calculating an absolute value from the in-module relative address and a starting address obtained by searching a program module which has the module name and a mechanism indicating the head at its head.

CONSTITUTION: A module name A and an in-module relative address 255 are inputted from the external input mechanism 1 and the module name A is passed to a module search control part 3 through a module name control part 21. The control part 3 searches all program modules 61W6n which have module names and mechanisms indicating their heads at their heads to find a module 61 having the module name A, and a module head address control part 4 obtains the head address A. An address calculation part 5 calculates the absolute address from this and the inputted in-module relative address 255 of the in-module relative address control part 22 to indicate a specified point.