Fingerprint image enhancement is an important process for improving the matching performance of low quality fingerprints. In order to eliminate high contrast noise lines such as deep wrinkles, which are prevalent in the low quality fingerprint images, we focus on the fact that true ridges have multiple paralleling neighbors. In this report, we propose the parallel ridge filtering method which can strongly suppress non-parallel noise lines by utilizing the parallelism of ridges. We also show the efficiency of our method by experimental results.