The invention provides a method for activating impurity element added to a semiconductor and performing gettering process in shirt time, and a thermal treatment equipment enabling to perform such the heat-treating. The thermal treatment equipment comprises treatment rooms of n pieces (n>2) performing heat-treating, a preparatory heating room, and a cooling room, and heating a substrate using gas heated by heating units of n pieces as a heating source, wherein a gas-supplying unit is connected to a gas charge port of the cooling room, a discharge port of the cooling room is connected to a first gas-heating unit through a heat exchanger, a charge port of an m-th (1.ltoreq.m.ltoreq.(n-1)) treatment room is connected to a discharge port of an m-th gas-heating unit, a charge port of an n-th treatment room is connected to a discharge port of an n-th gas-heating unit, a discharge port of the n-th treatment room is connected to the heat exchanger, and discharge port of the heat exchanger is connected to gas charge port of the preparatory heating room.