  We study the Kondo effect in heat transport via a local two-state system.
This system is described by the spin-boson Hamiltonian with Ohmic dissipation,
which can be mapped onto the Kondo model with anisotropic exchange coupling. We
calculate thermal conductance by the Monte Carlo method based on the exact
formula. Thermal conductance has a scaling form \kappa = (k_B^2 T_K/\hbar)
f(\alpha,T/T_K ), where T_K and \alpha indicate the Kondo temperature and
dimensionless coupling strength, respectively. Temperature dependence of
conductance is classified by the Kondo temperature as \kappa\propto (T/T_K )^3
for T\ll T_K and \kappa\propto (k_B T / \hbar\omega_c)^{2\alpha-1} for T\gg
T_K. Similarities to the Kondo signature in electric transport are discussed.
