Proximity sensor

An operation section is provided to a proximity sensor including: a detection section having an oscillation circuit and an amplification section having a function detecting a metal body using an oscillation amplitude of the oscillation circuit In a set mode, when an operation to set an adjustment value for a sensitivity adjustment (a sensitivity adjustment value) is conducted in an operation section CPU generates a sensitivity adjustment signal in digital quantity indicating the sensitivity adjustment value and outputs the signal to a D/A converter The sensitivity adjustment signal digital-to-analog converted by the D/A converter is given to a feedback circuit through a voltage adjustment circuit Since the feedback circuit is designed so as to change a feedback current quantity according to an applied voltage, a current with a magnitude matching a value the sensitivity adjustment signal is fed back to a resonance circuit to thereby control an oscillation amplitude.