  We propose that the importance of the quantum annealing procedure to find the
ground state of frustrated decorated bond systems where 'entropic slowing down'
happens due to peculiar density of states. Here, we use the time dependent
Schr\"odinger equation to analyze the real time dynamics of the process. It is
found that the quantum annealing is very efficient comparing to the thermal
annealing for searching the ground state of the systems. We analyze the
mechanism of quantum annealing from a view point of adiabatic process.
