A child seat mountable vehicle seat, includes: a seat skin including a front skin and a rear skin; a stitched portion; and a non-stitched portion formed in the stitched portion to define an opening from which a metal striker is projected. An extension portion of the front skin is turned over and extends forwards, while an extension portion of the rear skin extends forwards further than the metal striker. A trim plate is applied along an inner surface side of the rear skin, and in the non-stitched portion, the extension portion of the front skin is superposed on the extension portion of the rear skin with respect to a direction in which a latching device is moved to latch the metal striker.