A hinge mechanism capable of realizing an increase in durability, an improvement in feeling, and a reduction in size and weight in cell phones and note type personal computers for which a further reduction in size and weight is requested. In the hinge mechanism, one of two sets of cams in which rotating cams (4) are engaged with fixed cams (5) only one time through the angle of 360 DEG generates an energizing force at the start end of the rotating or opening/closing area of the hinge mechanism and the other set of cam generates an energizing force at the terminal end of the rotating or opening/closing area to generate the energizing forces at the start end and terminal end in any opening/closing area. By the hinge mechanism, the increase in durability, the improvement in feeling, and the reduction in size and weight can be realized.