reduction of the energy burden in a step of drying hydrous low - substituted hydroxypropyl cellulose , reduction of water content of a cake obtained by dehydration , and others are targeted . more specifically , provided is a method for dehydrating hydrous l - hpc with a compression type dehydrator by feeding the hydrous l - hpc to a screw conveyer connected to the inlet of the dehydrator , including steps of : starting the operation of the conveyer to fill the conveyer and the dehydrator with the hydrous l - hpc , starting the operation of the filled dehydrator , and feeding the hydrous l - hpc to the conveyer , while discharging dehydrated l - hpc from an outlet of the dehydrator , wherein a feed rate of feeding the hydrous l - hpc to the conveyer is equal to a discharge rate of discharging the dehydrated l - hpc in terms of net weight of cellulose ether , and a method for producing l - hpc by using the above method .