An electrocardiographic signal measurement apparatus that easily attaches or detaches and can stably measure electrocardiographic signals without obstructing motions of a user.An electrocardiographic signal measurement apparatus includes an outer ear electrode that is made of a material having elasticity and conductivity and is brought into contact with and attached to an area of an outer ear including a boundary region between an auricle and an earlobe configuring the outer ear, an upper arm electrode that is brought into contact with and attached to an upper arm on the opposite side in the horizontal direction to the side where the outer ear electrode is attached to the outer ear, and a signal processing unit that is connected with the outer ear electrode and the upper arm electrode and measures an electrocardiographic signal detected by the outer ear electrode and the upper arm electrode.