  We consider the finite temperature Casimir free energy acting on a spherical
shell in (D+1)-dimensional Minkowski spacetime due to the vacuum fluctuations
of scalar and electromagnetic fields. Dirichlet, Neumann, perfectly conducting
and infinitely permeable boundary conditions are considered. The Casimir free
energy is regularized using zeta functional regularization technique. To
renormalize the Casimir free energy, we compute the heat kernel coefficients
$c_n$, $0\leq n\leq D+1$, from the zeta function $\zeta(s)$. After
renormalization, the high temperature leading term of the Casimir free energy
is $-c_DT\ln T-T \zeta'(0)/2$. Explicit expressions for the renormalized
Casimir free energy and $\zeta'(0)$ are derived. The dependence of the
renormalized Casimir free energy on temperature is shown graphically.
