Abstract: A cartridge handling hand of a cartridge system sliding valve apparatus for a molten metal vessel is mountable to a general purpose robot. The hand includes a cartridge pressing cylinder secured to a mounting plate whose one side surface is provided with a device for mounting a carrier arm. A first pair of cylinder support arms for lock pins and a second pair of support arms are attached vertically to the other side surface of the mounting plate. Lock pins are attached to piston rod ends of cylinders which are secured to the cylinder support arms 2. Cartridge clamp arms are slidably fitted into guide pins provided vertically in the outside of the second pair of support arms. The cartridge clamp arms are coupled through a cylinder which opens or closes the arms. A cartridge system sliding valve apparatus includes positioning metal fittings for interfitting with the lock pins of the cartridge handling hand of the invention and positioning pins which fit in the positioning recesses of a cartridge.