Heat transfer characteristics in a pressurized He II channel, including a copper wall, were investigated experimentally and numerically. Temperature distributions in the channel and the wall were measured when the copper wall was heated. It was confirmed that the wall temperature increased remarkably in occurrences of a phase transition of helium in the channel. The value of stored energy in the copper wall when its upper or lower portion are heated locally are smaller than when the center portion of the wall is heated locally. Heat conduction through the copper heat transfer across interfaces (Kapitza conductance) and heat transport by internal convection of He II were all considered in the present two-dimensional time dependent numerical analyses. The numerical results were in qualitative agreement with the experimental results when the channel was filled with He II.