  We perform a perturbative computation of the glueball superpotential for N=1
supersymmetric G_2 gauge theory with one adjoint matter multiplet. We find that
the computation simplifies because the bosonic momentum integral cancels with
the fermionic momentum integral. The effective glueball superpotential allows
us to gain an insight into non-perturbative aspect of the supersymetric gauge
theory.
