  Microscopic theory of the normal-to-superconductor coexistence line of a 2D
two-band Weyl superconductor subjected to magnetic field is constructed. It is
shown that a Weyl semi-metal that is nonsuperconducting or having a small
critical temperature $T_{c}$ at zero field, might become a superconductor at
higher temperature when the magnetic field is tuned to a series of quantized
values $H_{n}$. The pairing occurs on Landau levels. It is argued that the
phenomenon is much easier detectable in Weyl semi - metals than in parabolic
band metals since the quantum limit already has been approaches in several Weyl
materials.. An experimental signature of the superconductivity on Landau levels
is the reduction of magnetoresistivity. This has already been observed in
$Cd_{3}As_{2}$ and several other compounds. The novel kind of quantum
oscillations of magnetoresistance detected in $ZrTe_{5}$ is discussed along
these lines.
