An optical member driving mechanism is provided, including a fixed portion, a movable portion, and a driving module, wherein the movable portion is movably connected to the fixed portion and includes an optical member holder and a spacing member. The optical member holder can support an optical member and has a surface facing the optical member. The optical member can change the moving direction of an external light. The spacing member is disposed between the surface and the optical member, and a gap is formed between the surface and the optical member. The driving module can drive the movable portion to move relative to the fixed portion.