  The two-photon two-neutrino interaction induced by magnetic field is
investigated. In particular the processes $\gamma \gamma \to \nu \bar \nu$ and
$\gamma \to \gamma \nu \bar \nu$ are studied in the presence of strong magnetic
field. An effective Lagrangian and partial amplitudes of the processes are
presented. Neutrino emissivities due to the reactions $\gamma \gamma \to \nu
\bar \nu$ and $\gamma \to \gamma \nu \bar \nu$ are calculated taking into
account of the photon dispersion and large radiative corrections. A comparison
of the results obtained with previous estimations and another inducing
mechanisms of the processes under consideration is made.
