A clip-type electrode includes a pair of clamping plates arranged to be opened and closed relative to each other about a common shaft and having concave surfaces facing each other, an electrode member mounted on one of the clamping plates, and a spring coiled around the common shaft for biasing the ends of the clamping plates remote from the common shaft towards each other. One of the clamping plates is longer than the other. The electrode member includes a strip of resilient, electrically conductive material bent into a U-shaped cross-section thus providing a pressuring plate section for applying pressure to the limb of a patient, and a pair of engagement plates each extending upwardly from opposing edges of the pressuring plate section and having plural inwardly projecting bosses. The engagement plates clamp the longitudinal edges of the longer one of the clamping plates for attaching the electrode member to the clamping plate. The pressuring plate section is brought into intimate contact with the surface of the skin of the patient's limb to make the contact resistance uniform and eliminate noise or distortion in the output waveform, thereby making possible accurate diagnosis of the condition of the heart. Since one of the pair of the clamping plates is longer than the other, the electrode is unlikely to be detached by movement of the limb.