A process for producing a cellulose derivative, comprising: a first step including reacting a cellulose and a first reactant comprising a long-chain reactant for reacting with a hydroxy group of the cellulose to introduce a long-chain organic group having 5 or more carbon atoms, in a solid-liquid heterogeneous system, to form a cellulose derivative in a swollen state, the cellulose derivative having the long-chain organic group having 5 or more carbon atoms introduced therein and having a part of hydroxy groups of the cellulose remained, and performing solid-liquid separation to obtain the cellulose derivative as an intermediate; and a second step including reacting the intermediate cellulose derivative and a second reactant comprising a short-chain reactant for reacting with a remaining hydroxy group of the intermediate cellulose derivative to introduce a short-chain organic group having 4 or less carbon atoms to form a final cellulose derivative having the short-chain organic group having 4 or less carbon atoms introduced therein.