A rectifier that is installed on a vehicle which includes a front shield at a front of a vehicle compartment, a hood in front of the front shield, a cowl between a back edge of the hood and a lower end of the front shield, and a fender on an outside of the hood and the cowl in a vehicle width direction, the rectifier including a rectifier member that is installed at a region on a side surface of the fender and adjacent to the back edge of the hood, and has a negative pressure generation part which causes an airflow created when the vehicle travels to generate a negative pressure backward. The front shield is shaped like a curved surface that projects toward a front of the vehicle. At least a part of the negative pressure generation part is disposed in front of a shield extension virtual curve.