  We have shown that the $B-L$ generation due to the decay of the thermally
produced superheavy fields can explain the Baryon assymmetry in the universe if
the superheavy fields are heavier than $10^{13-14}$ GeV. Note that although the
superheavy fields have non-vanishing charges under the standard model gauge
interactions, the thermally prduced baryon asymmetry is sizable. The $B-L$
violating effective operators induced by integrating the superheavy fields have
dimension 7, while the operator in the famous leptogenesis has dimension 5.
Therefore, the constraints from the nucleon stability can be easily satisfied.
