  The dynamics of the steady-state Sweet--Parker-type reconnection is analyzed
in relativistic regime when energy density in the inflowing region is dominated
by magnetic field. The structure of reconnection layer (its thickness, inflow
and outflow velocities) depends on the ratio of two large dimensionless
parameters of the problem - magnetization parameter $\sigma \gg 1$ (the ratio
of the magnetic to particle energy-densities in the inflowing region) and the
Lundquist number $S$. The inflow velocity may be relativistic (for $ S<
\sigma$) or non-relativistic (for $ S > \sigma$), while the outflowing plasma
is moving always relativisticly. For extremely magnetized plasmas with $\sigma
\geq S^2$, the inflow four-velocity becomes of the order of the \Alfven
four-velocity.
