Provided are a method and an apparatus for user authentication based on face recognition and handwritten signature verification, by which authentication accuracy in user authentication using a handwritten signature is further increased. The method including: receiving a handwritten signature of a user; acquiring a face image of the user who inputs the handwritten signature, simultaneously with the receiving of the handwritten signature; determining whether the user is a legitimate user, on the basis of characteristics information of the face image; adjusting a reference value for verification based on characteristics information of the handwritten signature, according to a result of determination based on the characteristics information of the face image; determining whether the user is the legitimate user, on the basis of the characteristics information of the received handwritten signature and the adjusted reference value.