A memory region for fingerprint images acquired from a sweep type fingerprint sensor is saved. A fingerprint reading system including a sweep type fingerprint sensor and a memory to store a partial fingerprint image read by the sensor includes an image acquisition unit which successively acquires partial fingerprint images by using the sweep type fingerprint sensor, a reconstruction unit which overlaps an acquired partial fingerprint image and an already acquired partial fingerprint image, stores a resultant image in the memory, and monitors whether a definite region has reached a predetermined size, a feature extraction unit which generates feature information of the fingerprint by using an image in the definite region when the definite region reached at the predetermined size in the reconstruction unit, and releases a memory portion corresponding to the definite region after the generation of feature information, and a feature construction unit which successively records generated feature information in accordance with its generation order. When the memory portion of the definite region is released, the reconstruction unit conducts subsequent reconstruction processing by using the memory portion.