The physical unclonable function (PUF) is a method to derive ID information peculiar to a device by detecting random physical features that cannot be controlled during the device’s manufacture. Because information such as the ID information is difficult to replicate, PUF is used as a technique to prevent forgery. PUF has two major application fields: an authentication scheme, and protection of intellectual property of the semiconductor industry. Several circuit systems to compose PUF have been reported. This study proposes a new PUF based on ring oscillator PUF. By incorporating a mechanism to correct the oscillation frequency dispersion that results from the layout, the proposed PUF can generate ID accurately. We verified the proposed PUF’s validity by conducting experiments using an FPGA that incorporates the proposed PUF.