Abstract: A friction hinge device includes a housing, and a torsion spring held fixed within the housing. The torsion spring has an outer surface with a predetermined diameter, an inner surface differentiating in diameter, and a breakthrough hole defined by the inner surface. The outer surface of the torsion spring has a protrusion. The inner surface of the torsion spring is formed with a pair of first diameter portions facing to each other and second diameter portions disposed between the first diameter portions. The second diameter portion has a diameter greater than the diameter of the first diameter portion. A shaft bar is fitted into the breakthrough hole of the torsion spring such that a center portion of the shaft bar tightly contacts the first diameter portion of the torsion spring.