To understand transition characteristics from wood to charcoal, Quercus variabilis wood was carbonized at 200, 250, 300, 340, 540 and $740^{circ}C$, respectively. Heating value, pH and surface property by FT-IR spectroscopy of the carbonized charcoal were investigated. Heating value and pH increased with increasing carbonization temperature from 4500 cal/g and 4.3 of the control wood to 8,000 cal/g and 9 of the charcoal carbonized at $740^{circ}C$, respectively. From FT-IR spectroscopy, the peaks from O-H, C-H and C-O stretching disappeared during carbonization at 540 and $740^{circ}C$. Aromatic skeletal vibration at near $1,506{sim}1,593cm^{-1}$ was repidly increased until $540^{circ}C$. These results suggest that the chemical and physical characteristics of wood components in cell wall can be easily changed by increasing carbonization temperature and the carbonization seem to be incomplete at temperature below $540^{circ}C$.