A flow rectifier (1) for an axial fan (2), having a base body (3) which has rings (4a, 4b, 4c, 4d, 4e) delimited radially inside the outside by cylindrical surfaces (5, 6). Air guide vanes (7) which are distributed in the circumferential direction about a longitudinal axis (X-X) arranged in a generally radial manner and extend between the cylindrical surfaces (5, 6). The air guide vanes (7), in the circumferential direction, extend with a curvature (R1) relative to the axial direction (X-X) between an inflow-side vane edge (7a) and an outflow-side vane edge (7b). In order to minimize the divergence of airflow from the flow rectifier (1), two or more rings (4a, 4b, 4c, 4d, 4e) having air guide vanes (7) are provided in the base body (3).