a seat for a vehicle in which a seat back is separated into a plurality of portions in the vertical direction and a reclinable angle of each of the plurality of separated portions can be varied is disclosed , which includes a reclining device provided in connection with the lowest portion of the separated portions and a cushion of the seat for adjusting a reclinable angle of the lowest portion relative to the cushion of the seat , a plurality of angle adjusting devices each provided in connection with adjacent ones of the separated portions for adjusting an angle of an upper portion of the adjacent ones relative to a lower portion thereof , a fine adjusting member provided in connection with each of the plurality of angle adjusting devices for finely adjusting the angle of the upper portion , a member for coupling each of the plurality of angle adjusting devices to the reclining device to thereby operate the plurality of angle adjusting devices in response to each operation of the reclining device , whereby the separated portions can be varied to various reclinable postures and the reclined postures of the separated portions can be adjusted finely .