A housing of a projection apparatus suitable for accommodating a heat source is provided. The housing includes an outer casing and a heat conductive element. The outer casing has an inner wall. Furthermore, the outer casing is suitable for enclosing the heat source. The heat conductive element is disposed on the inner wall between the outer casing and the heat source. Moreover, an insulated chamber is formed between the heat conductive element and the outer casing. The insulated chamber prevents the heat source from directly heating the outer casing and provides a better heat insulation.