A portable electronic device and a movable lens-shutting module thereof are provided. The movable lens-shutting module includes a magnetic field generator, a rotatable driving assembly and a movable shutter assembly. The rotatable driving assembly includes a rotatable magnetic element and a rotatable driving element fixed on the rotatable magnetic element. The rotatable driving element includes at least one driving rod. The movable shutter assembly includes at least one shutter element. The shutter element includes a lens opening corresponding to a lens and a receiving groove for receiving the driving rod. When the rotatable magnetic element and the rotatable driving element are concurrently moved by a magnetic force generated by the magnetic field generator, the shutter element is moved in a linear direction by moving the driving rod, so that the lens is exposed by the lens opening or is blocked by the shutter element.