We examined the physico–chemical properties of the biochar produced from orange peel, residual wood, and water treatment sludge at different pyrolytic temperatures from 300 to 700℃. In the peel biochar (OPB) and wood biochar (RWB), pH and carbon content tended to increase with increasing pyrolytic temperature and were higher than those in the sludge biochar (WSB). The electrical conductivity of the OPB was the highest, while specific surface area of the RWB was the highest among the three types of biochar. The specific surface area was relatively high in any biochar. Any biochar surface displayed by scanning–electron–micrographs revealed many hollow channels and very heterogeneous forms. Unlike the WSB, surface functional groups of the OPB and RWB were similar in intensity and shape. From characteristic results of pH, specific surface area, and functional groups, the biochar derived from orange peel, residual wood, and water treatment sludge may have a possibility to be used as an environmental–cost effective soil amendment and adsorbent.