A biosignal measuring apparatus (100, 200, 250, 300, 350, 500, 600, 700, 750, 800, 850, 1010), comprising: a first interfacing unit (110, 210, 260, 310, 360, 410, 510, 610, 710, 760, 810, 860) comprising two or more interfaces (212; 214, 262; 264, 312; 314, 362; 364, 412; 414; 416, 512; 514, 612; 614, 712; 714, 762; 764, 812; 814, 862; 864) configured to detect first signals from a subject; a second interfacing unit (120, 220, 270, 320, 370, 420, 520, 610, 710, 760, 810, 860) comprising two or more interfaces (222; 224, 272; 274, 322; 324, 372; 374, 422; 424, 522; 524, 612; 614, 712; 714, 762; 764, 812; 814, 862; 864) configured to detect noise from the subject, wherein the two or more interfaces of the second interfacing unit comprise electrolytes, and wherein the second interfacing unit further comprises a connecting unit (226, 276, 326, 376, 426) comprising an electrolyte configured to connect the electrolytes of the two or more interfaces of the second interfacing unit, and to decrease a resistance among the two or more interfaces of the second interfacing unit to detect noise; and a biosignal extracting unit (130, 230, 280, 330, 380, 530, 630, 730, 780, 830, 880) configured to extract a biosignal of the subject from the first signals by using signals output from the second interfacing unit, wherein, to extract the biosignal from the first signals, the biosignal extracting unit is further configured to remove a signal output from a twenty-first interface of the second interfacing unit from a signal output from an eleventh interface of the first interfacing unit, remove a signal output from a twenty-second interface of the second interfacing unit from a signal output from a twelfth interface of the first interfacing unit, and perform differential amplification on signals generated as a result of the removed signal of the twenty-first interface of the second interfacing unit and the removed signal of the twenty-second interface of the second interfacing unit. a first interfacing unit (110, 210, 260, 310, 360, 410, 510, 610, 710, 760, 810, 860) comprising two or more interfaces (212; 214, 262; 264, 312; 314, 362; 364, 412; 414; 416, 512; 514, 612; 614, 712; 714, 762; 764, 812; 814, 862; 864) configured to detect first signals from a subject; a second interfacing unit (120, 220, 270, 320, 370, 420, 520, 610, 710, 760, 810, 860) comprising two or more interfaces (222; 224, 272; 274, 322; 324, 372; 374, 422; 424, 522; 524, 612; 614, 712; 714, 762; 764, 812; 814, 862; 864) configured to detect noise from the subject, wherein the two or more interfaces of the second interfacing unit comprise electrolytes, and wherein the second interfacing unit further comprises a connecting unit (226, 276, 326, 376, 426) comprising an electrolyte configured to connect the electrolytes of the two or more interfaces of the second interfacing unit, and to decrease a resistance among the two or more interfaces of the second interfacing unit to detect noise; and a biosignal extracting unit (130, 230, 280, 330, 380, 530, 630, 730, 780, 830, 880) configured to extract a biosignal of the subject from the first signals by using signals output from the second interfacing unit, wherein, to extract the biosignal from the first signals, the biosignal extracting unit is further configured to remove a signal output from a twenty-first interface of the second interfacing unit from a signal output from an eleventh interface of the first interfacing unit, remove a signal output from a twenty-second interface of the second interfacing unit from a signal output from a twelfth interface of the first interfacing unit, and perform differential amplification on signals generated as a result of the removed signal of the twenty-first interface of the second interfacing unit and the removed signal of the twenty-second interface of the second interfacing unit.