A key-board assembly is described that has a key-mat and a keyboard PCB aligned with respect to each other instead of first to a housing of an input device. The lever is composed of a lever body made of a plastic and a reinforcement plate assembled with the plastic lever body. Preferably, the electrical and mechanical vibrations are at the same frequency and phase with respect to each other, in order to increase the absorption effect. Electrodes are disposed over the respective resistors for fixing a resistance of the resistors, the electrodes being made of the same material as that of the gate electrode of the MOS transistor.