Embodiments provide a hinge mechanism and a foldable mobile terminal. A swing arm component and a synchronization component are disposed on both sides of a main shaft component of the hinge mechanism, so that when a swing arm rotates around the main shaft component, a synchronization arm on a same side as the swing arm rotates accordingly to drive a synchronization arm and a swing arm on the other side to rotate, and further, housings on both sides of the foldable mobile terminal including the main shaft component can move synchronously, and force of a flexible screen is relatively even. In addition, because swing arms on both sides of the main shaft component rotate around different axes, through such a design, accommodation space that can accommodate the flexible screen can be formed during rotation of the swing arms, so that damage to the flexible screen is reduced.