PURPOSE: To analyze the parallelization possibility of a program on a computer having a single CPU.

CONSTITUTION: A program input part 1 reads a program including a parallelization instruction line. A first program execution part 2 executes the program read by the program input part 1 in accordance with the processing sequence. A parallelization instruction line detection part 3 searches the parallelization instruction line in the program and detects a processing part for which a parallelization possibility analysis is to be performed. A processing sequence shuffling part 4 changes the execution sequence of the processing part detected by the parallelization instruction line detection part 3. A second program execution part 5 executes the program for which the processing sequence is changed. An acceptance or rejection decision part 6 compares the execution result of the program executed by the first program execution part 2 with the execution result of the program executed by the second program execution part 5. Thus, the parallelization possibility analysis can be performed without using a parallel computer.