The invention provides an ECM (electret condenser microphone) switching circuit, comprising a detection circuit and an SPDT (single-pole double-throw) electronic switch, wherein the SPDT (single-pole double-throw) electronic switch is used for switching between an ECM into a pitching-in ECM unit in a normal circuit in accordance with switching signals output by the detection circuit; the detection circuit comprises detection points, a detection signal extracting unit and a detection signal processing unit, wherein the detection signal extracting unit is used for extracting detection signals of the detection points and transmits the detection signals to the detection signal processing unit, and the detection signal processing unit is used for processing the detection signals and outputting the switching signals to the SPDT electronic switch. The switching circuit externally provides a first contact and a second contact, and the first and second contacts are used for being connected with two pins of the pitching-in ECM unit; the first contact is connected with the detection signal extracting unit; and the detection points are arranged on the line on which the first contact locates. According to the invention, the DC (direct current) characteristic of a JFET (junction field-effect transistor) inside the ECM is well utilized, thus realizing the automatic switching scheme with the fewest contacts and low cost.