The present invention relates to a biosensor, including: a blood cell separation membrane which separates blood cells from blood and allows plasma components to pass through； a microfluid channel through which the plasma components that have passed through the blood cell separation membrane flow； a lower substrate which allows the plasma components that have passed through the blood cell separation membrane to flow along the microfluid channel； and a pillar which connects the blood cell separation membrane and the lower substrate, in which an electrode is disposed in the pillar, and the pillar pushes and lifts the blood cell separation membrane by a predetermined distance. The biosensor of the present invention allows plasma, which is difficult to pass through the blood cell separation membrane due to surface tension, to easily pass through.
