  Supersymmetric contribution to the muon anomalous magnetic moment a_\mu is
discussed in the no-scale-type supersymmetry breaking scenarios. Taking the
correlation between the supersymmetric contributions to a_\mu and Br(b\to
s\gamma), it is shown that the precise measurements of these quantities serve
an important constraint on the relative sign of the gaugino masses; combining
the 2.6-\sigma deviation in a_\mu from the standard-model prediction measured
by the E821 experiment and Br(b\to s\gamma) measured by CLEO, the sign of the
product M_2M_3 is strongly preferred to be positive, where M_2 and M_3 are
SU(2)_L and SU(3)_C gaugino mass parameters, respectively. In particular,
no-scale-type models with universal gaugino masses are in accord with the two
constraints and also with the Higgs mass bound. In addition, it is also shown
that future improvements in the measurements of a_\mu and Br(b\to s\gamma) may
provide serious test of the cases with M_2M_3<0.
