PROBLEM TO BE SOLVED: To obtain a fingerprint acquisition system which is accurate and highly reliable by accepting a biometric image only when one or more components are in respectively assigned ranges. SOLUTION: A force detecting device 665 senses a force or torque applied to the fingerprint image acquisition system. The force or torque that an image forming device 660 receives is transferred to a force sensor 665 to be measured. The force sensor 665 generates a stream of force data and a computer 610 reads a stream of force or torque of data. A sensor 665 measures the force that an object applies when the contacting of a fingerprint of the object is sensed. The force and torque that the object applies are monitored intermittently by the computer 610 and a biometric image is optionally selected and displayed. When the image is acquired, the force and torque are analyzed by the computer 610 and when the pressure is extremely high or low, or when the shearing torque is high, the image is excluded.