Position detection device for an astride riding type vehicle

The present invention relates to a position detection device having a first member and a second member, which are capable of relative displacement to each other, the first member comprising a magnet, and the second member comprising a first magnetic field property sensor for outputting a detection signal of a reference position from a magnetic field property of a magnetic field formed by the magnet, wherein the magnet has an S-pole section and an N-pole section that are arranged side by side in the direction of the relative displacement; and the first magnetic field property sensor is configured so as to receive magnetic force from the magnet at all times throughout a range in which the first member and the second member are displaceable relative to each other.