A headrest apparatus for an MPV includes a headrest that can be automatically completely housed in a storage space in such a way as to slide without requiring a user to perform an additional operation of pushing the headrest downwards, thus being more convenient for the user. The headrest apparatus has a simple structure and a reduced size, thus reducing the weight of the vehicle. The headrest apparatus includes a headrest sliding unit, a sinking seat folding unit, and a seat support frame supporting a sinking seat on a floor of the MPV, wherein, when the sinking seat is housed in a seat storage space formed in the floor of the MPV, the upper surface of the sinking seat that is in a housed state is level with the upper surface of the floor of the MPV.