To provide a water-soluble cellulose ether composition that is improved in fluidity and other flow properties to attain much better coating property, when it is applied as a sizing agent for wall paper and shows excellent work efficiency, economy and the like by adding a specific surfactant to the sizing composition.

This cellulose ether composition comprises a water-soluble cellulose ether and a fluidity-promoting agent. In this case the fluidity-promoting agent is a poly-ether compound or its derivative or an organic phosphorus surfactant.