Patent ID: 6930477

Claim:
A rotation angle detection device comprising: a permanent magnet fixedly secured to a rotating member, and having an S pole side face and an N pole side face; a first guide member having its one end face fixedly attached to the S pole side face of said permanent magnet; a second guide member having its one end face fixedly attached to the N pole side face of said permanent magnet, and having its tip end disposed in opposition to a tip end of said first guide member; and a magnetoresistive member disposed in a space formed between the tip end of said first guide member and the tip end of said second guide member, said magnetoresistive member being fixedly attached to a non-rotating member; wherein an angle of rotation of said rotating member is detected by detecting a change of the azimuth of magnetic flux, which is generated by said permanent magnet in said space, by means of said magnetoresistive member.