Abstract: A keyboard assembly for electronic musical instruments such as electronic pianos is constructed from a key switch unit and a resilient holder block for mounting the key switch unit to a key frame via simple snap coupling. The key switch unit includes a resiliently deformable movable contact common to all keys in combination with given printed circuits including a plurality of fixed contacts so that, when any key is depressed, the movable contact is locally depressed by an actuator accompanying the key and brought into provisional contact with a corresponding fixed contact in order to selectively switch on a corresponding printed circuit for generation of a musical tone.