To provide a magnetic field detecting device capable of suppressing the effects of unnecessary magnetic fields which occur outside and inside on the detection of the location of movement, the detection of the angle of rotation, etc.

The magnetic field detecting device 100 is provided with a magnet 112 to generate a magnetic field, a magnetic field detecting element 132 to detect the intensity of the magnetic field generated by the magnet 112, and magnetic shields 141 and 142 each made of a soft magnetic body to suppress that the magnetic field detecting element 132 detects the intensity of magnetic fields except the magnetic field generated by the opposing magnet 112. The magnetic shields 141 and 142 are arranged in the vicinity of both sides of the magnetic field detecting element 132 and with respect to the magnetic field detecting element 132 in the direction which intersects at approximately right angles the direction in which the magnetic field detecting element 132 is moved to the magnet 112.