Abstract: A Rotation angle sensor includes the following elements: (a) a sensor housing; (b) a rotor unit having at least one segment magnet, mounted for rotation in the housing; (c) a stator unit having a magnetic flux detection device, mounted in the housing adjacent the rotor; (d) a bearing shaft unit having a bearing shell and a radial shaft seal, mounted in the housing, the bearing shaft forming a shaft receiver recess mounted in the rotor unit; and (e) a rotor actuation unit inserted into the shaft receiver recess. The rotor actuation unit includes a shaft element for moving the rotor unit with respect to the stator unit, whereby during manufacture, the bearing shell is inserted into the housing unit at least to the point of the rotor unit, and the radial shaft seal is inserted behind it, and the shaft element is pressed past the radial shaft seal and the bearing shell into the shaft receiver recess.