A vehicle seat sliding apparatus includes a first rail adapted to be fixed to any one of a vehicle floor and a seat; and a second rail adapted to be fixed to the other one of the vehicle floor and the seat. The second rail includes an in-rail functional portion formed at an end portion of the first rail in terms of the longitudinal direction so as to project into an internal space formed by the first rail to achieve a predetermined function; a recessed portion formed around the in-rail functional portion in association with the formation of the in-rail functional portion; and a protector adapted to be mounted on an end portion of the first rail in terms of the longitudinal direction and cover the end portion thereof. The protector is formed with a projection adapted to fit the recessed portion to couple the protector and the first rail.