To avoid damages to a reactive member which reacts with cleaning gas.

This heat treatment equipment is provided with a treatment chamber 23, a susceptor which is arranged in the treatment chamber and retains a wafer, a heater 27 for heating a wafer, a straightening plate 30 arranged in the treatment chamber so as to face opposite the wafer, a gas inlet pipe 31 which is connected with the treatment chamber and supplies a cleaning gas into the treatment chamber, and a reactive member composed of a material which reacts with the cleaning gas. In a cleaning method of the equipment, the reactive gas and inert gas are made to flow to a part on which deposits due to heat treatment hardly stick, and the cleaning gas is exhausted through dilution or carrying, where the reactive member exists.