Abstract: By placing a single C59N molecule in a double-barrier tunnel junction we have realized a new type of single molecule rectifier device based on the single electron tunneling effect and the special electronic structure of the C59N molecule. In our experiments the positive onset voltage is about 0.5—0.7 V, while the negative onset voltage is about 1.6—1.8 V. Theoretical analyses show that the half-occupied Fermi level of the neutral C59N molecule and the asymmetric shift of the Fermi level when the molecule is charged are responsible for the molecular rectification. The principle of this molecular device ensures the stability and repeatability of its rectifying properties.