A rotor position detection device comprising a sensor including a first chip and a second chip which are aligned with a first line and detect a change in magnetic flux in a sensing magnet , wherein the sensor has the first line which is inclined with respect to a second line passing through any one of the first chip and the second chip in a radial direction of the sensing magnet , wherein the sensing magnet include a main magnet and a sub-magnet disposed outside of the main magnet , wherein N-pole split magnets and S-pole split magnets in the sub-magnet are alternately disposed in a circumferential direction, each split magnet having a width (w), wherein a distance (P) between the first chip and the second chip in a circumferential direction of the sensing magnet is smaller than the width (w) of the split magnet in the circumferential direction of the sensing magnet , wherein the width (w) of the split magnet is set with respect to a center of the sub magnet in the radial direction of the sensing magnet , wherein the first chip and the second chip are aligned on one split magnet , wherein the sensor includes a first chip and a second chip in one body hereof, characterized in that a distance (d1) from an intersecting point of a first line and a reference line (C3) to the first chip is the same as a distance (d2) from the intersecting point of the first line and the reference line (C3) to the second chip , in that the first line is a reference line with which the first chip and the second chip are aligned, and in that the reference line (C3) is a reference line in the circumference direction, which passes through centers of lengths of the sub-magnets in the radial direction of the sensing magnet . wherein the sensor has the first line which is inclined with respect to a second line passing through any one of the first chip and the second chip in a radial direction of the sensing magnet , wherein the sensing magnet include a main magnet and a sub-magnet disposed outside of the main magnet , wherein N-pole split magnets and S-pole split magnets in the sub-magnet are alternately disposed in a circumferential direction, each split magnet having a width (w), wherein a distance (P) between the first chip and the second chip in a circumferential direction of the sensing magnet is smaller than the width (w) of the split magnet in the circumferential direction of the sensing magnet , wherein the width (w) of the split magnet is set with respect to a center of the sub magnet in the radial direction of the sensing magnet , wherein the first chip and the second chip are aligned on one split magnet , wherein the sensor includes a first chip and a second chip in one body hereof, characterized in that a distance (d1) from an intersecting point of a first line and a reference line (C3) to the first chip is the same as a distance (d2) from the intersecting point of the first line and the reference line (C3) to the second chip , in that the first line is a reference line with which the first chip and the second chip are aligned, and in that the reference line (C3) is a reference line in the circumference direction, which passes through centers of lengths of the sub-magnets in the radial direction of the sensing magnet . <EOS>