This invention provides a cell made of polymers for spectra measurement while inhibiting a decrease in a molecular weight of resin caused by discharge treatment and having a stable hydrophilic modified surface. The hydrophilic resin cell is prepared by providing a polymeric resin cell between the two opposing electrodes, applying an electric field to a region between the above opposing electrodes under a nitrogen atmosphere with a pressure close to the atmospheric pressure to generate an electric discharge, and exposing the cell subjected to discharge treatment with a gas including oxygen.