  The magnetization process of the S=3/2 antiferromagnetic Heisenberg chain
with the single-ion anisotropy D at T=0 is investigated by the exact
diagonalization of finite clusters and finite-size scaling analyses. It is
found that a magnetization plateau appears at m=1/2 for $D>D_c=0.93 \pm 0.01$.
The phase transition with respect to D at D_c is revealed to be the
Kosterlitz-Thouless-type. The magnetization curve of the infinite system is
also presented for some values of D.
