Two isomorphous TMTSF cation radical salts with tetrachlorometalate anion, TMTSF.FeCl4 (rho rt = 40 Omega cm), and TMTSF.GaCl4 (rho rt = 20 Omega cm) were prepared. The crystal containing tetrachloroferrate anion undergoes an antiferromagnetic ordering below T-N = 4K with the easy axis perpendicular to the TMTSF stacking direction. X-ray crystallographic analysis of the crystal reveals that Cl atoms of the anions closely contact with Se atoms of the donor molecules and suggests that the spin ordering is mediated by magnetic interaction between donors and anions.