Abstract: In a portable electrocardiograph, a first measuring electrode that is to be held by a hand during measurement and comes into contact with the palm is provided on a body case. A second measuring electrode that to be pressed against the chest is provided on an arm member provided on the body case in foldable manner. The arm member is placed on the surface facing the body case when the arm member is folded onto the body case. Therefore, to measure electrocardiographic waves with this electrocardiograph, the user has only to slide the arm member into the opening between buttons on the front of his or her clothes or the opening in the shirt at the armpit, and then contacts the second measuring electrode with his chest for measurement. Therefore, it is not necessary to apply the apparatus perpendicularly to the chest. The user has only to place the apparatus almost in parallel to the chest and press the second measuring electrode against the left side of the heart in the chest.