In this study, biochars were prepared from Japanese cedar sawdust with a mechanical compression at different temperatures in an air atmosphere. The compression pressure at a given constant value was applied to the raw material during the torrefaction process. Experimental results indicated that the compression positively improved the fuel properties of the biochar obtained. The carbon content in biochar increased; whereas the oxygen and hydrogen contents decreased. The H/C ratio of biochar was generally proportional to its 0/C ratio, and biochars prepared at temperatures of more than 300 degrees C were in proximity to bituminous or sub-bituminous coals in the van Krevelen diagram. Torrefaction at 300 degrees C and 3 MPa gave biochar with a higher heating value of 29.8 MJ/kg and an energy yield of 0.85. Furthermore, the differential thermal analyses showed that the peaks corresponding to the release of volatile matters from biochar decreased with an increase in the compressive load. Consequently, torrefaction of Japanese cedar sawdust with compression in an air atmosphere would be a promising method to produce biochars as an alternative fuel.