A magnetic sensing surface of a stroke sensor is placed in an angular range between a first imaginary line and a second imaginary line. The first imaginary line is an imaginary line that coincides with a center line between first and second magnets of a magnetic movable body when a wastegate valve is placed to have a full close degree of the wastegate valve. The second imaginary line is an imaginary line that coincides with the center line between the first and second magnets when the wastegate valve is placed to have a half degree between the full close degree and a full open degree of the wastegate valve.