  We analyze the meson correlator in the spatial direction at finite
temperature. To achieve fine resolution in the spatial direction, we use an
anisotropic lattice with the standard Wilson plaquette gauge action and the
$O(a)$ improved Wilson quark action. Below and above $T_c$, properties of
correlators are investigated by two methods: fits with ansatz for the spectral
function, and direct reconstruction of the spectral function using the maximum
entropy method.
