A turbine housing assembly including a plurality of constituent members connected to one another to constitute a turbine housing into which a turbine wheel rotated by exhaust gas introduced from an engine is insertable, the turbine housing assembly at least comprising: a scroll part of a bottomed cylindrical shape that has a surrounding wall part and a bottom face part , the scroll part including: an exhaust gas flow path of a spiral shape formed inside the bottomed cylindrical shape and configured such that exhaust gas that has flowed in from an exhaust gas inlet flows through the exhaust gas flow path ; and an exhaust gas outlet having a through hole formed on the bottom face part , the exhaust gas outlet being configured such that the exhaust gas that has flowed through the exhaust gas flow path flows out from the exhaust gas outlet ; and an exhaust part of a tubular shape comprising a separate body separate from the scroll part , the scroll part being formed by processing a single piece of sheet metal so that, on a back face side of the bottom face part of the scroll part , a recess portion through which the trough-hole of the exhaust gas outlet is formed and a projecting portion formed by a bottom surface of the exhaust gas flow path projecting toward the back face side are formed, the projecting portion surrounding the recess portion , characterized in the recess portion of the scroll part being connected to an end portion of the exhaust part in a turbine axial direction so that the exhaust part is in communication with the exhaust gas outlet of the scroll part in a state where the end portion of the exhaust part is not in contact with the projecting portion of the scroll part and a gap (a) is formed between an outer circumferential face of the exhaust part and the projecting portion of the scroll part . a scroll part of a bottomed cylindrical shape that has a surrounding wall part and a bottom face part , the scroll part including: an exhaust gas flow path of a spiral shape formed inside the bottomed cylindrical shape and configured such that exhaust gas that has flowed in from an exhaust gas inlet flows through the exhaust gas flow path ; and an exhaust gas outlet having a through hole formed on the bottom face part , the exhaust gas outlet being configured such that the exhaust gas that has flowed through the exhaust gas flow path flows out from the exhaust gas outlet ; and an exhaust part of a tubular shape comprising a separate body separate from the scroll part , an exhaust gas flow path of a spiral shape formed inside the bottomed cylindrical shape and configured such that exhaust gas that has flowed in from an exhaust gas inlet flows through the exhaust gas flow path ; and an exhaust gas outlet having a through hole formed on the bottom face part , the exhaust gas outlet being configured such that the exhaust gas that has flowed through the exhaust gas flow path flows out from the exhaust gas outlet ; and an exhaust part of a tubular shape comprising a separate body separate from the scroll part , the scroll part being formed by processing a single piece of sheet metal so that, on a back face side of the bottom face part of the scroll part , a recess portion through which the trough-hole of the exhaust gas outlet is formed and a projecting portion formed by a bottom surface of the exhaust gas flow path projecting toward the back face side are formed, the projecting portion surrounding the recess portion , characterized in the recess portion of the scroll part being connected to an end portion of the exhaust part in a turbine axial direction so that the exhaust part is in communication with the exhaust gas outlet of the scroll part in a state where the end portion of the exhaust part is not in contact with the projecting portion of the scroll part and a gap (a) is formed between an outer circumferential face of the exhaust part and the projecting portion of the scroll part . <EOS>