Abstract: An electrocardiogram detector including a pad, an electrical connection unit, a plurality of retaining members, and a plurality of electrode pieces is disclosed. The pad has a first face, a second face, and a plurality of through-holes. The electrical connection unit has an electrical connection port and a plurality of conducting lines electrically connected to the electrical connection port. The plurality of conducting lines is arranged on the first face of the pad. The plurality of retaining members is fixed to the first face of the pad and electrically connected to the plurality of conducting lines. The plurality of electrode pieces is electrically connected to the plurality of retaining members. The plurality of electrode pieces is fixed by the plurality of retaining members. In this arrangement, convenient operation of the electrocardiogram detector is improved.