To provide a high purity carboxymethylcellulose salt with less amount of salts obtained as byproducts at the production of the carboxymethylcellulose salt, and a method for producing the same.

The carboxymethylcellulose salt contains less than 1 wt.% of inorganic salts and a glycolic acid salt. The method for producing such carboxymethylcellulose containing the salts of less than 1 wt.% comprises irradiating ultrasonic waves to a carboxymethylcellulose salt containing an organic solvent and inorganic salts and a glycolic acid salt produced as byproducts at the time of reaction thereby removing these salts.