We study the temperature dependence of the pion decay constant and rho-meson
mass in the hidden local symmetry model at one loop. Using the standard
imaginary time formalism, we include the thermal effect of rho meson as well as
that of pion. We show that the pion gives a dominant contribution to the pion
decay constant and rho-meson contribution slightly decreases the critical
temperature. The rho-meson pole mass increases as T^4/m_\rho^2 at low
temperature dominated by the pion-loop effect. At high temperature, although
the pion-loop effect decreases the rho-meson mass, the rho-loop contribution
overcomes the pion-loop contribution and rho-meson mass increases with
temperature. We also show that the conventional parameter a is stable as the
temperature increases.Comment: We added a comment on the correction to the rho-meson mass from the
omega-pi loop. This is the final version to be published in Phys. Rev. D. 19
pages (LaTeX-RevTeX), 7 PostScript figure