PROGRAM INSPECTION DEVICE

PROBLEM TO BE SOLVED: To improve efficiency in debugging by a system programmer, by performing validity check in which problematic places in a program can be easily detected.SOLUTION: A program inspection device comprises: a detection part 12C which acquires an object file of a program which uses instruction words compliant with IEC 61131-3, and detects places or factors which may cause action failure of the program, using a variable or a constant obtained by simulating a stack operation of machine language step by step; and a display processing part 12D which displays the places and the factors detected in the detection part 12C. The detection part 12C includes at least one of following functions: a function 12C1 for detecting a place which accesses outside of a variable area, using the variable or the constant obtained during a process of simulation; a function 12C2 for detecting a place of a possible infinite loop; a function 12C3 for detecting a place which may lack accuracy of data; and a function 12C4 for detecting a place in which a condition may not be satisfied.