A temperature control method for a reversing type heat exchanger group wherein an outlet temperature of reheating gas of an arbitrarily selected reversing type heat exchanger which serves as a reference in the reversing heat exchanger group is rendered equal in value to a reference control temperature set beforehand in such a manner so as to satisfy the sweeping temperature difference. The outlet temperatures of the reheating gas in the other reversing type heat exchangers of the reversing type heat exchanger group are rendered equal in value to the outlet temperature of the reheating gas in the reversing type heat exchanger serving as the reference. Thus, the temperature of the cold end of all of the reversing type heat exchangers of the reversing type heat exchanger group are caused to be balanced equally whereby ice and dry ice deposited on the feed water channels can be effectively removed by a sweeping action.