  We theoretically predict a generation of a current in Weyl semimetals by
applying circularly polarized light. The electric field of the light can drive
an effective magnetic field of order of ten Tesla. For lower frequency light, a
non-equilibrium spin distribution is formed near the Fermi surface. Due to the
spin-momentum locking, a giant electric current proportional to the effective
magnetic field is induced. On the other hand, higher frequency light realizes a
quasi-static Floquet state with no induced electric current. We discuss
relevant materials and estimate order of magnitude of the induced current.
