The Schwinger operator method is applied for the study of the CP-odd pure gluonic effective Lagrangian in the Standard Model at the three-loop level. The induced θ-term vanishes for the same reasons as the electric dipole moments (EDMs) of the quark and the W-boson in the two-loop approximation. A simple way is found to demonstrate these cancellations. All other terms of the effective Lagrangian acquire non-vanishing contributions. The effective operator of dimension six, the Weinberg operator, is calculated explicitly. The corresponding contribution to the EDM of the neutron is much smaller than that which comes from large distances.