Disclosed are a biosensor electrode structure and a biosensor including the biosensor electrode. The biosensor electrode structure includes a working electrode that penetrates a subject and includes an enzyme that changes a first electrical response corresponding to a first electrical stimulation applied to the subject to a second electrical response in the subject, and first and second impedance electrodes that contact the subject and receive the first electrical response and the second electrical response from the subject, and that are spaced apart from each other.