Raw material ingredients for glass and manufacturing method of optical glass

To provide raw material ingredients for glass for stably manufacturing lanthanum-containing optical glass having required optical properties and a manufacturing method of optical glass for stably manufacturing the optical glass. In a manufacturing method of optical glass by blending raw material ingredients for glass which are used for manufacturing optical glass by blending with other kinds of raw material ingredients for glass, and by heating and melting, and which is comprised of powder-like lanthanum oxide that is in a sealed state where moisture is shut-off, with a plurality kind of raw material ingredients for glass, and by heating and melting, the manufacturing method for optical glass comprises blending immediately after above raw material ingredients for glass are opened or reserving them in a dry atmosphere or in a reduced pressure and dry state after they are opened and until blending.