To efficiently recycle an old plastic sheet by using a new form capable of biologically separating color information or particularly a plastic capable of recycling by melting.

An old plastic sheet which has not been used is suitably mechanically comminuted by a cutter and/or a comminutor 3. To decolor the comminuted information carrier, after the carrier is introduced into a container 4, the carrier is cleaned, and colors of the information are separated. Thereafter, a pure material of the carrier sheet is melted in a melting device 5, thereby obtaining a material to be used as a new information carrier sheet. After the carrier sheet is drawn by a known sheet drawing device, the sheet is cut into band-like or particularly entirely cut in a cutter 7. Then, the entire sheet is again treated in machine 1, 2 or the like, and particularly adhering information is introduced.