An immersion-nozzle replacement apparatus comprising: a guiding means supporting at least two immersion nozzles (2, 2a, 2b), a foremost immersion nozzle and a rear immersion nozzle following the foremost immersion nozzle, the two immersion nozzles (2, 2a, 2b) having an upper flange with a sprue port, and a lower tube, the guiding means including two rows each of which is disposed parallel to one another on both sides of the tube, of each of the immersion nozzles (2, 2a, 2b) to support a lower face in the flange of each of the immersion nozzles (2, 2a, 2b) while coming into contact with a side face in the flange of each of the immersion nozzles (2, 2a, 2b) horizontally; and a pressing keyboard row provided in each of the rows of the guiding means, and including a plurality of first keyboards pressing the lower face in the flange of the foremost immersion nozzle onto a flow-out port in a molten-metal retainer; the immersion-nozzle replacement apparatus pushing out the foremost immersion nozzle horizontally with the rear immersion nozzle, as well as putting the rear immersion nozzle on each of the pressing keyboard rows; characterized in that the guiding means further includes an additionally-pressing keyboard row which is disposed adjacent to a rear side of each of the pressing keyboard rows and includes at least one second keyboard pressing the lower face in the flange of the rear immersion nozzle before pushing out the foremost immersion nozzle; and the second keyboard pressing a front end side of the lower face in the flange of the rear immersion nozzle so as to provide the flange of the rear immersion nozzle at a leading end thereof with a height, which is identical with a height that the flange of the foremost immersion nozzle has, when the rear immersion nozzle is moved to a position at which the rear immersion nozzle neighbors the foremost immersion nozzle horizontally. a guiding means supporting at least two immersion nozzles (2, 2a, 2b), a foremost immersion nozzle and a rear immersion nozzle following the foremost immersion nozzle, the two immersion nozzles (2, 2a, 2b) having an upper flange with a sprue port, and a lower tube, the guiding means including two rows each of which is disposed parallel to one another on both sides of the tube, of each of the immersion nozzles (2, 2a, 2b) to support a lower face in the flange of each of the immersion nozzles (2, 2a, 2b) while coming into contact with a side face in the flange of each of the immersion nozzles (2, 2a, 2b) horizontally; and a pressing keyboard row provided in each of the rows of the guiding means, and including a plurality of first keyboards pressing the lower face in the flange of the foremost immersion nozzle onto a flow-out port in a molten-metal retainer; the immersion-nozzle replacement apparatus pushing out the foremost immersion nozzle horizontally with the rear immersion nozzle, as well as putting the rear immersion nozzle on each of the pressing keyboard rows; characterized in that the guiding means further includes an additionally-pressing keyboard row which is disposed adjacent to a rear side of each of the pressing keyboard rows and includes at least one second keyboard pressing the lower face in the flange of the rear immersion nozzle before pushing out the foremost immersion nozzle; and the second keyboard pressing a front end side of the lower face in the flange of the rear immersion nozzle so as to provide the flange of the rear immersion nozzle at a leading end thereof with a height, which is identical with a height that the flange of the foremost immersion nozzle has, when the rear immersion nozzle is moved to a position at which the rear immersion nozzle neighbors the foremost immersion nozzle horizontally.