  We investigate the differential system with affine Weyl group symmetry of
type A^{(1)}_4 and construct a space which parametrizes all meromorphic
solutions of it. To demonstrate our method based on singularity analysis and
affine Weyl group symmetry, we first study the system of type A^{(1)}_2, which
is the equivalent of the fourth Painlev\'e equation, and obtain the space which
augments the original phase space of the system by adding spaces of codimension
1. For the system of type A^{(1)}_4, codimension 2 spaces should be added to
the phase space of the system in addition to codimension 1 spaces.
