The aim of this study was to examine the possibility to use two petroleum based solvents, kerosene and a distillate rich in benzene (A150), as practical solvents for the degradative solvent extraction at 350 degrees C in reference to 1-MN. It was found that the thermal degradation behavior of two biomass samples, a rice straw and Leucaena, in the three solvents was rather similar and that only the distribution of Soluble, Deposit, and Residue was affected by the difference of solubility of the solvents. Preparation of solvent treated biomass (STB) using the three solvents gave the yields close to the sum of the yields of Soluble, Deposit, and Residue. It was judged that A150 may be used to preparing Soluble and that Kerosene can well be used to prepare STB.