A hinge mechanism includes a first rotation assembly, a second rotation assembly substantially parallel to the first rotation assembly, a brace member, a connection shaft partially received in the sliding slot, a first connection member, and a second connection member. The first rotation assembly includes a first pivoting shaft and a first bracket sleeved on the first pivoting shaft. The first bracket includes a mounting portion eccentrically formed on one end of the first bracket. The second rotation assembly includes a second pivoting shaft and a second bracket sleeved on the second pivoting shaft. The second bracket includes a mounting portion eccentrically formed on the second bracket. The brace member defines a sliding slot. An end of the first connection member is eccentrically connected to the first pivoting shaft, and the other end of the first connection member is connected to the connection shaft.