Abstract: The present invention relates to a jet regulator (1) having a jet fractionating device inside a mounting housing (6). The jet regulator (1) according to the present invention is characterized in that the mounting housing (6) is divided into at least two housing parts (7, 8), and that the housing parts (7, 8) can be connected to one another, and that a housing part (7) at the flow inlet side is connected fixedly and non-releasably with the jet fractionating device (2). The jet regulator (1) according to the present invention is distinguished by a high degree of shape stability and by manufacturing costs that are nonetheless low, even for small housing diameters (see FIG. 1).