In a fingerprint matching processor which has an electrostatic capacity semiconductor sensor 14 for detecting fingerprint information based on electrostatic capacities between a plurality of detection electrodes 21 arranged on a semiconductor substrate 24 at a predetermined interval in a two dimensional manner and a target object, and which executes a fingerprint matching process for the detected fingerprint information, a water repellent film 30 is formed on a protective film 26, the protective film 26 protecting ground electrodes 22 that are disposed between the detection electrodes 21 and configured to ground the target object and the detection electrodes 21, and serves as a surface of the semiconductor sensor 14 for placement of the target object.