The present invention relates to a method for producing an alkali cellulose with suppressed decrease in the degree of polymerization as well as with small use amount of a basic compound, and to a method for producing a cellulose ether by using the alkali cellulose thus obtained. Provided by the present invention are: (A) a method for producing an alkali cellulose, comprising Step 1 wherein a cellulose-containing raw material (I) is treated by a pulverizing machine thereby obtaining a cellulose-containing raw material (II) which contains a cellulose having crystallinity in the range of 10 to 55% and Step 2 wherein the cellulose-containing raw material (II) obtained in Step 1 is added by a basic compound with the amount thereof being in the range of 0.6 to 1.5 mol relative to 1 mol of an anhydroglucose unit that constitutes the said cellulose as well as by water with the amount thereof being in the range of 20 to 100% by mass relative to the said cellulose thereby obtaining the alkali cellulose; and (B) a method for producing a cellulose ether by reacting the alkali cellulose produced by the foregoing production method with an etherification agent.