Molten aluminium is equilibrated with pure carbon over a temperature range of 800° to 1400°C under the pressure of 4×10-5mm Hg, and atmosphere. of argon Solubility of carbon in liquid aluminium under pres sure of 4×10-5mmHg is 0.10, 0.14, 0.16, and 0.32wt% at 800°, 1000°, 1100°, and 1200° respectively, and is high compared with the value obtained in the atmosphere of argon. The difference of solubility data was discussed as based on the existence of small amount of oxygen in the system. Solibility of carbon in solid aluminium is estimated to be 0.015wt% from the analytical data of graphite carbon.