A sliding nozzle apparatus in which components constituting the sliding nozzle apparatus are less likely to be damaged even when a surface pressure is loaded with no refractory plate mounted. The sliding nozzle apparatus comprises a fixed metal frame and a sliding metal frame which is slidably provided with respect to the fixed metal frame. The sliding metal frame is movable between a first position where, in a state where two refractory plates are mounted, respectively, in a plate-receiving recess of the fixed metal frame and a plate-receiving recess of the sliding metal frame, a surface pressure can be loaded between the two refractory plates, and a second position where, in a state where no refractory plate is mounted to either plate-receiving recess, a surface pressure can be loaded between the fixed metal frame and the sliding metal frame.