A position detection apparatus includes a magnetic generator, a magnetic detector, a storage, and a rotation angle calculator. The rotation angle calculator calculates a relative rotation angle of the magnetic generator with respect to the magnetic detector based on a voltage output from the magnetic detector and a relational expression of θ=sin−1((VH−c)/V0)−b. In the relational expression, the relative rotation angle is defined as θ, the voltage output from the magnetic detector is defined as VH, a true maximum value of the voltage output from the magnetic detector is defined as V0, a first true correction value is defined as b, and a second true correction value is defined as c.