A sensor electrode device comprises a base and a plurality of flexible electrodes. The flexible electrodes protrude from one side of the base, detecting at least one physiological signal and sending out the physiological signal via the base. The flexible electrodes can expel hairs to directly contact the skin, whereby hairs would not hinder the sensor electrode device from detecting physiological signals. Further, the tips of the flexible electrodes bend under pressure to increase the area contacting the skin and improve the ability to detect physiological signals.