In order to minimize change in base position from which an output representative of the
angle of rotation of a rotary shaft (2) relative to a housing (1) is based, to reduce the number of component parts used, to enable a load acting on the rotary shaft (2) to be supported and to enable a rotational angle sensor
assembly to be assembled with a simplified
machining operation, the rotational angle sensor
assembly includes a rotational angle detecting means (3) for detecting the
angle of rotation between mutually opposed first and second rotational angle detectors (3A) and (3B). A housing (1) is of a cup-shaped configuration having a hollow defined therein, with the first rotational angle
detector (3A) disposed at the bottom of the housing hollow. The second rotational angle
detector (3B) is mounted on one end of the rotary shaft (2) that is rotatably supported by rolling bearings (4). The bearings (4) are pre-loaded at a predetermined pressure by a spring member (6). A portion of the rotary shaft (2) remote from the first rotational angle
detector (3A) extends outwardly from an opening (1f) of the housing (1).