A clamper includes a base, a movable element, a sliding element, a connecting bar, a clamping element and a first elastic element. The movable element is movable in a first direction relative to the base. The sliding element is movable in a second direction relative to the base. The connecting bar connects the movable element and the sliding element. The clamping element sets on the sliding element. The first elastic element includes a terminal setting on the sliding element.