A method of storing a sputtering target made of lanthanum oxide, wherein a lanthanum oxide target to which a lanthanum fluoride film was formed and lanthanum oxide powder are charged in a vacuum pack with an oxygen transmission rate of 0.1 cm3/m2 per 24 h at 1 atm or less and a moisture vapor transmission rate of 0.1 g/m2 per 24 h or less, and, after charging the target and the powder, the vacuum pack is subject to vacuum suction and sealing for storage. This invention aims to provide technology for enabling the long-term storage of a sputtering target in a usable state by devising the method of storing a target made of an oxide of lanthanum as a rare earth metal, and thereby inhibiting the pulverization phenomenon of the target caused by the hydration (hydroxylation) of such target due to residual air or the inclusion of air, and the pulverization phenomenon caused by the formation of carbonate.