A stroke sensor system includes a vehicle-body-side member, a wheel-side member, and a movement-amount deriving section. The movement-amount deriving section derives a movement amount of relative movement between the vehicle-body-side member and the wheel-side member. At least a part of one of the vehicle-body-side member and the wheel-side member is a conductor, and the other is provided with a coil. The movement-amount deriving section includes an even number of capacitors and an even number of exciting sections. The even number of capacitors are electrically coupled to the coil and configure an LC resonance section. The even number of exciting sections are for exciting an oscillation waveform output by the LC resonance section. The even number of capacitors and the even number of exciting sections are divided into equal numbers to configure a balanced circuit. The movement-amount deriving section derives the movement amount based on the oscillation waveform.