1. A display and edit device for a program containing function blocks, said device comprising: a program memory for storing a program to be processed; a block definition analyzer for accessing said program stored in said program memory and analyzing structure relationship of function block definitions contained in said program; a block instance analyzer for accessing said program stored in said program memory and analyzing structure relationship of function block instances contained in said program; and a structure display device for causing to display structure relationship of the analyzed structure relationship of said function block definition and structure relationship of the analyzed structure relationship of said function block instance.