When a front link and a rear link are respectively rotated about stationary end side shaft portions (43 and 53) as rotation axes, movable end side shaft portions (45 and 55) of the front link (41) and the rear link (51) can move in a vertical direction. A rotational range of the front link (41) is set such that the movable end side shaft portion (45) of the front link (41) can always be positioned above a rotational center connection line (L). Conversely, a rotational range of the rear link (51) is set such that the movable end side shaft portion (55) of the rear link (51) can be positioned over a range that straddles the rotational center connection line (L). Thus, only the movable end side shaft portion (55) of the rear link (51) can be raised while the movable end side shaft portion (45) of the front link (41) is lowered until a position of a movable end connection line (M) is switched from a lower side position to an upper side position with respect to the stationary end side shaft portion (53) of the rear link (51). As a result, the seat cushion can be advantageously lifted up at a getting in/out time of the occupant such that a relative height of the buttocks of the occupant to the knees of the occupant can be increased.
