A biosensor measuring an analyte contained in a sample is provided, including: an insulative lower substrate that has at least one electrode on which an enzyme reaction layer reacting with the analyte is formed; an upper substrate that faces the lower substrate and is made of a conductive material; and an adhesive layer that has a sample feed with a predetermined height on the enzyme reaction layer and attaches the upper and lower substrates to each other, where an end of the upper substrate acts as an electrode in which an electron-transfer mediator contained in the enzyme reaction layer is oxidized or reduced, and the other end acts as an electrical contact part that electrically contacts a measurement unit.