We prepared an organic conductor crystal having extremely high electron mobility, in which the adamantylidene (Ad) derivative of La@C-82 (an endohedral metallofullerene known as a n-type semiconductor) is aligned in an orderly fashion. The single-component crystal exhibits high electron mobility of mu > 10 cm(2) V-1 s(-1) along the c axis under normal temperatures and pressures in the atmosphere, as shown by flash-photolysis time-resolved microwave conductivity (TRMC) measurements, which are the highest of reported organic conductors measured by TRMC. According to density functional calculations, the single crystal of La@C(82)Ad is semi-metallic, with a small band gap of 0.005 eV.