A wearable electronic device and method are disclosed, including: at least one sensor including a plurality of electrodes, at least one processor operatively connected with the at least one sensor, and a memory operatively connected with the at least one processor. The processor implements the method, including detecting coupling of the wearable electronic device with an external accessory contacting a body of a user, and based on detecting the coupling with the external accessory, measuring a biometric signal using a voltage received from at least two electrodes from among a plurality of measurement electrodes included in the external accessory.