Endohedral metallofullerene Ca@C-60 has been prepared by arc-heating of graphite rod containing calcium oxide, CaO, and extracted by pyridine under the oxygen-free condition. The laser desorption time-of-flight (LD-TOF) mass spectrum of the pyridine solution exhibits five main peaks due to C-60+, Ca@C-60+ C-70+, Ca@C-70+, and C-74+. It has been found that Ca@C-60 can be extracted only under the atmosphere of degassed pyridine owing to its high oxygen-sensitivity.