In this talk, we introduce a new mechanism of direct baryogenesis by baryon number violating effective operator which is analogous to neutron-antineutron oscillation after electroweak symmetry breaking. Sufficient amount of the baryon asymmetry can be produced through the flavor oscillation after inflaton/moduli decay by the operator during the energy loss processes. We also suggest the mechanism could be searched by terrestrial experiments such as neutron-antineutron oscillation experiments as well as collider experiments.