A capacitive sensor device for use with a steering wheel is provided. The steering wheel includes a rim and a spoke that is connected to the inner side of the rim, and the sensor device is provided on the spoke. The sensor device includes an electrode configured to be capacitively coupleable to an object to be detected, and includes a controller configured to detect a change in capacitance of the electrode, and determine whether the object is in proximity to the rim or the spoke based on the change in the capacitance of the electrode. The change in the capacitance occurs in response to the object being in proximity to the rim or the spoke.