  We derive the Wilsonian renormalization group equation in two dimensional
${\cal N}=2$ supersymmetric nonlinear sigma models. This equation shows that
the sigma models on compact Einstein K\"{a}hler manifolds are aymptotically
free. This result is gerenal and does not depend on the specific forms of the
K\"{a}hler potentials. We also examine the renormalization group flow in a new
model which connects two manifolds with different global symmetries.
