Torsion of bars with uniform cross-sections has been studied by many researchers, and the problem is well known as Saint-Venant torsional one. However, a few researchers have investigated as three dimensional problem. In this paper, the author conducted numerical simulation of torsion test by the finite element method using finite element software. Numerical examples are shown for typical four kinds of cross-sections. Tortional moment and twist angle per unit length subjected to concentrated loads at the end of the bars are compared with analytical solution. Finally, the validity of saint-Venant problem is proved.