A turbocharger comprising: a bearing housing that rotationally supports an impeller shaft; a turbine housing that is a cast component coupled to an end of the bearing housing in a rotation axis direction of the impeller shaft, wherein exhaust gas discharged from an internal combustion engine flows inside the turbine housing; a turbine chamber defined in the turbine housing; a turbine impeller that is accommodated in the turbine chamber and is configured to be rotated integrally with the impeller shaft by exhaust gas drawn into the turbine chamber; a turbine scroll passage that is defined in the turbine housing and is a part of a passage for conducting exhaust gas that has flowed into the turbine housing to the turbine chamber, the turbine scroll passage surrounding a circumference of the turbine chamber; a connecting passage that is defined in the turbine housing and connects the turbine scroll passage and the turbine chamber to each other; an annular metal plate that constitutes a part of a wall surface of the connecting passage; and a scroll passage defining plate that includes a passage defining portion that is arranged such that a predetermined clearance is provided between the passage defining portion and the turbine housing, the passage defining portion constituting a part of a wall surface of the turbine scroll passage, and an inner circumferential edge that extends from an inner circumferential edge portion of the passage defining portion and along the metal plate, characterised in that the scroll passage defining plate is arranged in the turbine housing such that the inner circumferential edge is fixed, and an outer circumferential edge portion of the passage defining portion that is on a side opposite from the inner circumferential edge portion is movable relative to the turbine housing. a bearing housing that rotationally supports an impeller shaft; a turbine housing that is a cast component coupled to an end of the bearing housing in a rotation axis direction of the impeller shaft, wherein exhaust gas discharged from an internal combustion engine flows inside the turbine housing; a turbine chamber defined in the turbine housing; a turbine impeller that is accommodated in the turbine chamber and is configured to be rotated integrally with the impeller shaft by exhaust gas drawn into the turbine chamber; a turbine scroll passage that is defined in the turbine housing and is a part of a passage for conducting exhaust gas that has flowed into the turbine housing to the turbine chamber, the turbine scroll passage surrounding a circumference of the turbine chamber; a connecting passage that is defined in the turbine housing and connects the turbine scroll passage and the turbine chamber to each other; an annular metal plate that constitutes a part of a wall surface of the connecting passage; and a scroll passage defining plate that includes a passage defining portion that is arranged such that a predetermined clearance is provided between the passage defining portion and the turbine housing, the passage defining portion constituting a part of a wall surface of the turbine scroll passage, and an inner circumferential edge that extends from an inner circumferential edge portion of the passage defining portion and along the metal plate, characterised in that the scroll passage defining plate is arranged in the turbine housing such that a passage defining portion that is arranged such that a predetermined clearance is provided between the passage defining portion and the turbine housing, the passage defining portion constituting a part of a wall surface of the turbine scroll passage, and an inner circumferential edge that extends from an inner circumferential edge portion of the passage defining portion and along the metal plate, characterised in that the scroll passage defining plate is arranged in the turbine housing such that the inner circumferential edge is fixed, and an outer circumferential edge portion of the passage defining portion that is on a side opposite from the inner circumferential edge portion is movable relative to the turbine housing.