There is provided a method for producing a low polymerization degree cellulose ether having a less yellowish appearance and having excellent long-term storage stability through depolymerization of a high polymerization degree cellulose ether with an acid and without requiring an additive other than the acid. More specifically, there is provided a method for producing a low polymerization degree cellulose ether, including a step of depolymerizing a high polymerization degree cellulose ether with an acid to obtain a low polymerization degree cellulose ether mixture and a step of neutralizing the acid present in the low polymerization degree cellulose ether mixture, wherein ultraviolet is applied in the step of depolymerizing or between the steps of depolymerizing and neutralizing.