Disclosed is a method for manufacturing a biosensor comprising (a) forming an insulating layer in an electrode region; (b) coating the first photoresist layer on the insulating layer; (c) performing the first exposing process on the first electrode region through the first photomask; (d) removing unexposed area of the first photoresist layer except for the first electrode region using development; (e) coating the second photoresist layer on the first electrode region and the insulating layer after the step (d); (f) performing the second exposing process on the second electrode regions through the second photomask; (g) performing the third exposing process on the top portion of the second photoresist layer through a photomask with open areas in the shape of micro-sized wires connecting the second electrode regions; (h) removing the second photoresist layer except for the portions exposed in the steps (c), (f) and (g) using development.