A damper device includes an outer cylinder, an inner cylinder disposed inside the outer cylinder and having an inner chamber, a lower open end, and an upper closed end wall with a vent hole, a piston disposed in the inner chamber and having a passageway, a check valve coupled to the passageway to permit only upward flowing of a working fluid in the inner chamber through the passageway, and a piston rod having a lower rod end disposed outwardly of the outer cylinder, and an upper rod mounted to permit the piston to slide with the piston rod. The sliding of the piston rod is dampened by sliding of the piston in the inner chamber. A hinge assembly including the damper device is also disclosed.