Rotation sensing device

A rotation sensing device, which is a rotation sensing device for sensing the rotation of a rotating body, comprising:

• a single substrate having an insertion hole into which the rotating body is inserted;
• a magnetic field-generating member rotating with the rotation of the rotating body;
• a plurality of magnetic sensors disposed around the magnetic field-generating member;
• a casing which accommodates the plurality of magnetic sensors and is provided on the substrate;
• an optical sensor provided on the substrate on the side facing away from the plurality of magnetic sensors;
• and
• an optical disk which is disposed facing the substrate, with the optical sensor interposed therebetween, and which rotates with the rotation of the rotating body,
• wherein said device has an adjustment mechanism capable of adjusting the position of the plurality of magnetic sensors with respect to the magnetic field-generating member by adjusting the position of the casing relative to the substrate once the position of the optical sensor relative to the optical disk has been adjusted and the substrate has been precisely positioned.