An effective interaction spontaneously arising in a renormalizable model   of quantum field theory
  Theory of massless scalar field $\phi$ with interaction $g \phi^3$ in six-dimensional space is considered. A possibility of initial scale invariance breaking, which results in a spontaneous arising of effective interaction $G \phi^4$, is studied by application of Bogolubov quasi-averages approach. It is shown, that compensation equation for form-factor of this interaction in approximation up to the third order in $G$ has a non-trivial solution. The conditions imposed on form-factor value at zero and scalar field mass $m$ fix the unique solution, which gives relations between parameters of interaction $g \phi^3$ and parameters $G $ and $m$. Arguments are laid down in favour of a stability of the non-trivial solution. 
Boris A. Arbuzov