To obtain a process for producing a low-mol.-wt. cellulose ether having a high storage stability by irradiating a mixture comprising a high-mol.-wt. cellulose ether and a base with an accelerates electron beam.

A mixture comprising a high-mol.-wt. cellulose ether and a base is irradiated with an accelerated electron beam. The cellulose ether used has a viscosity-average mol.wt. of 50,000-500,000 g/mol, pref. examples being methylcellulose, a nonionic or ionic mixed methylcellulose ether, hydroxyethylcellulose, or a nonionic or ionic mixed hydroxyethylcellulose ether. The base used is a water-sol. inorg. salt having a buffer action and is used in an amt. of 0.01-4 wt.% of the cellulose ether. A suitable radiation source is a continuous electron beam accelerator.