  We report fluctuation magnetoconductance in a MgB2 superconductor prepared
under a high pressure of 3 GPa. This excess magnetoconductance,
$\Delta\sigma(H)$, follows the three-dimensional scaling function for the
critical fluctuations proposed by Ullah and Dorsey. This feature is inferred to
originate from the isotropic nature of the MgB2 compound.
