In a sliding nozzle comprising three plates consisting of an upper plate, an intermediate plate capable of a sliding movement, and a lower plate, it is intended to suppress adhesion and deposition of metal oxides and others on wall surfaces of inner bores of the three plates. The intermediate plate has: a first inclined portion whose surface defines a slidingly closing directional leading-side wall surface of an inner bore thereof and extends obliquely downwardly in a diametrically contracting direction; a second inclined portion whose surface defines an upper part of a slidingly closing directional trailing-side wall surface of the inner bore thereof and extends obliquely downwardly in a diametrically contracting direction, and a third inclined portion whose surface defines a lower part of the slidingly closing directional trailing-side wall surface of the inner bore thereof and extends obliquely downwardly in a diametrically expanding direction.