Abstract: The invention relates to a jet regulator (100) having a jet regulator housing (2), in the housing interior of which a flow straightener is provided, said flow straightener having at least one insert part (8, 9) that is insertable into the housing interior, said insert part (8, 9) having a grid structure which is formed from a set of radially oriented webs (13, 13?) which intersect or are in contact with a set of concentrically encircling webs (15) at intersection points (14) or contact points, and having at least one aeration opening (4) which passes through a housing circumferential wall (3) of the jet regulator (100). The jet regulator (100) according to the invention is characterized by the fact that the flow straightener has at least one insert part (8) with radially oriented webs (13), the free web end of which protrudes beyond the outer encircling web (15) and ends at a distance from the housing inner circumference of the jet regulator housing (2) (cf. FIG. 1).