A semiconductor manufacturing apparatus for cleaning a semiconductor substrate comprises a high-temperature circulation type chemical bath which is filled with a chemical to be used for cleaning of a semiconductor substrate and in which the chemical is circulated and reused, a draining mechanism which drains the chemical in the chemical bath therefrom, an auxiliary fluid supplying mechanism which adds to the drained chemical regarded as a waste chemical an auxiliary fluid, and thereby heats the waste chemical, a heat exchanger in which the heated waste chemical is stored temporarily and a new chemical is allowed to flow, and which cools the waste chemical and raises temperature of the new chemical by heat exchange, and a pipe in which the new chemical having the temperature raised in the heat exchanger is supplied to the chemical bath.