A rotation angle detecting device that detects a rotation angle of a rotating object includes a permanent magnet that generates magnetic fields in response to rotation of the rotating object, a magnetic sensor, a first yoke and a second yoke. The magnetic sensor includes a pair of close integrated magnetic sensing elements, such as hall elements, disposed at a position around the permanent magnet so that one of the sensing elements senses magnetic field at a phase different from the other. The first yoke and the second yoke forms two magnetic paths crossing each other at the magnetic sensor.