A biometric authentication apparatus for authenticating users, comprising: an ID acceptor configured to accept input of a user ID; a personal template fetcher configured to fetch a personal template corresponding to the user ID, the personal template containing registered biometric feature data and registered biometric shape data of a body part of a user; a verification sensor configured to obtain input biometric feature data of a partial area of the body part of the user, the verification sensor having a detection area smaller than a detection area of a registration sensor used in registering the registered biometric feature data; a guide information presenter configured to present guide information to guide, in accordance with the registered biometric shape data and data indicating a position of a verification area, the user to place his or her body part over the verification sensor so as to obtain the input biometric feature data in a partial area of the body part which corresponds to the verification area, the verification area being within the body part providing biometric features corresponding to the registered biometric feature data, the verification area corresponding to the detection area of the verification sensor, the verification area providing the highest density of the biometric features among partial areas each corresponding to the detection area of the verification sensor and contained within the detection area of the registration sensor; and a biometric feature verifier configured to verify the input biometric feature data in comparison with the registered biometric feature data in the verification area. an ID acceptor configured to accept input of a user ID; a personal template fetcher configured to fetch a personal template corresponding to the user ID, the personal template containing registered biometric feature data and registered biometric shape data of a body part of a user; a verification sensor configured to obtain input biometric feature data of a partial area of the body part of the user, the verification sensor having a detection area smaller than a detection area of a registration sensor used in registering the registered biometric feature data; a guide information presenter configured to present guide information to guide, in accordance with the registered biometric shape data and data indicating a position of a verification area, the user to place his or her body part over the verification sensor so as to obtain the input biometric feature data in a partial area of the body part which corresponds to the verification area, the verification area being within the body part providing biometric features corresponding to the registered biometric feature data, the verification area corresponding to the detection area of the verification sensor, the verification area providing the highest density of the biometric features among partial areas each corresponding to the detection area of the verification sensor and contained within the detection area of the registration sensor; and a biometric feature verifier configured to verify the input biometric feature data in comparison with the registered biometric feature data in the verification area.