The present invention relates to an information-recording medium for recording and reproducing information by using light and a method for recording information for the purpose of high-speed and high-density recording. The medium has a structural unit having a conductive polymer layer and an electrolyte layer sandwiched by a pair of electrode layers, each of which contains a thermally decomposable or crosslinkable compound. The medium described above allows high-speed rotation of the medium as it has a narrower range heated during recording and is more tolerant of displacement of auto-focusing or tracking, and also allows high-speed and high-density recording. The medium also allows lamination of multiple layers and easier selection of layers therein.