A banknote storage device includes a housing member having a loading region in which a banknote is loaded; a storage which is disposed to be adjacent to the housing member and in which the banknote is stored; a temporary accumulation region provided between the loading region and the storage so as to temporarily accumulate the banknote to be stored in the storage; and a push-in mechanism that pushes the banknote loaded to the loading region, into the temporary accumulation region and that pushes a plurality of the banknotes accumulated in the temporary accumulation region, into the storage.