A mobile unit with fingerprint sensor, includes a fingerprint sensor; a circuit board on which a plurality of circuit components are mounted, one of the circuit components processes an output signal output from the fingerprint sensor; a key case on which a plurality of key switches, used as operation keys of the mobile unit, are arranged, the key case being fixed to the circuit board; and a sensor-specific board that is provided separately from the circuit board and includes the fingerprint sensor thereon, and that is detachably attached to the key case and the fingerprint sensor is arranged adjacent to the operation keys.