Magnetic pole direction detection device

A magnetic pole direction detection device for detecting a magnetic pole direction of a detecting target magnet attached to a tip of a rotating shaft, the magnetic pole direction detection device comprising:

• a magneto-resistive element that comprises a magnetization fixed layer and a free layer;
• a magnetic detection unit that detects a change in a magnetic field generated by rotation of the detecting target magnet by the magneto-resistive element and outputs detection signals having different phases;
• a magnetic pole direction calculation unit that calculates a magnetic pole direction of the detecting target magnet based on the detection signals output from the magnetic detection unit;
• a direction correction amount calculation unit that calculates a direction correction amount for correcting an error, which is caused by a magnetization direction deviation of the magnetization fixed layer of the magneto-resistive element generated by action of the magnetic field of the detecting target magnet and is included in the magnetic pole direction calculated by the magnetic pole direction calculation unit;
• and
• a magnetic pole direction correction unit that corrects the magnetic pole direction calculated by the magnetic pole direction calculation unit by using the direction correction amount calculated by the direction correction amount calculation unit.