A position sensor including: a power supply terminal to which a power supply voltage is applied; a ground terminal to which a ground voltage is applied; an output terminal that outputs a signal; a detection portion that operates based on the power supply voltage and the ground voltage, and detects a position of a detection target by a magnetic resistance element whose resistance value changes according to a movement of the detection target; and a signal processing portion that operates based on the power supply voltage and the ground voltage, and processes a signal input from the detection portion.