  We present a new formula to numerically construct configurations in
rotational equilibrium, which consist of multiple layers. Each layer rotates
uniformly or differentially according to cylindrical rotation-laws that are
different from layer to layer. Assuming a different barotropic equation of
state (EOS) for each layer, we solve the Bernoulli equation in each layer
separately and combine the solutions by imposing continuity of the pressure at
each boundary of the layers. It is confirmed that a single continuous
barotropic EOS is incompatible with the junction condition. Identifying
appropriate variables to be solved, we construct a convergent iteration scheme.
For demonstration, we obtain two-layered configurations, each layer of which
rotates rapidly with either an "$\Omega$-constant law" or a "$j$-constant law"
or a "$v$-constant law". Other rotation laws and/or a larger number of layers
can be treated similarly. We hope that this formula will be useful in studying
the stellar evolution in multi-dimension with the non-spherical configuration
induced by rotation being fully taken into account.
