Position detecting device

A position detecting device comprising:

• a shaft;
• a casing supporting the shaft rotatably about an axis of the shaft;
• a magnetic circuit unit secured to the shaft and configured to rotate together with the shaft;
• a sensor attached to the casing, the sensor including:
• a sensor body;
• a magnetic detector protruding from the sensor body toward the magnetic circuit unit;
• and
• at least one engagement protrusion extending from the sensor body in vicinity of the magnetic detector and engaging with an engagement hole disposed on the casing,
• an anti-rotation hole disposed on one of the sensor body and the casing at a position spaced apart from the engagement hole of the casing;
• and
• an anti-rotation pin disposed on another of the sensor body and the casing, the anti-rotation pin engaging with the anti-rotation hole to prevent the casing and the sensor body from rotating relatively to each other about the engagement hole, wherein
• at least a part of the at least one engagement protrusion is in contact with an inner wall of the engagement hole on a straight line connecting a center of the magnetic detector and a center of the anti-rotation pin.