A keyboard apparatus includes a plurality of keys each rotatable with a predetermined stroke, a support assembly which includes a support with one side rotatably arranged with a support rail and a jack with the one side rotatably supported by the support, and rotates with depression of any of the plurality of keys, a hammer unit which is operated by receiving an action of the jack, a shank rail which rotatably supports the hammer unit, and a jack stopper which makes contact with the jack which rotates with the depression of any of the plurality of keys, the jack stopper being placed on a rotation path of the jack and provided to a fixing portion which does not rotate with the depression any of the plurality of keys.