Electrochemical dehumidification using a proton conducting ceramic as a solid electrolyte was studied. The working principle, based on the electrochemical hydrogen pump, is elucidated and experimental studies on this type of device an described. It was verified that the dehumidifier using a SrCeO3-based proton conducting ceramic worked successfully on a laboratory-scale and that the dehumidifier could desiccate the test gas to 6.7 Pa (dew point: about -45 degreesC). This type of device may be a convenient dehumidifier suitable for use in small, closed systems in scientific instruments.