A keyboard apparatus for an electronic musical instrument having white keys and black keys capable of providing a satisfactory tactile impression, having a satisfactory appearance, and suppressing a difference in tactile impression between when the white keys are played and when the black keys are played. Each white key has a base portion and an upper plate portion fixed to an upper surface of the base portion, and each black key has a key main body portion. The upper plate portion is formed by a porous member having sweat-absorbability and made of a material comprised of an AS resin mixed with stone powder and a white-colored colorant. Each black key is made of the same material as that of the upper plate portion, except for a colorant mixed therein.