A lens driving mechanism is provided, configured to drive an optical lens, including a bottom plate, a movable portion, an elastic member, and a biasing assembly. The movable portion is disposed on the bottom plate and has a base and a holder, wherein the holder is configured to hold the optical lens, and the holder is movably connected to the base. The elastic member connects the movable portion to the bottom plate. The biasing assembly connects the bottom plate and the movable portion and is configured to force the movable portion to move relative to the bottom plate. When the holder moves to a lower-limit position relative to the base, the holder comes into contact with the elastic member.