Optical writing device, optical reading device, recording-medium writing method, including wobble signal evaluation features

When performing writing and/or reading of information to/from an optical disk provided with a wobble including time axis information, an occurrence of a reading error of the time axis information from the wobble is suppressed so that disabled reading of information from the optical disk and an occurrence of a writing error can be prevented. Evaluated parameters such as a CRC error rate of an ATIP signal, an FMDT jitter amount and a phase error between an ATIP synchronization signal and a frame synchronization signal of writing data are evaluated based on a range of set values. When the evaluated parameter is deviated from the range of set values, writing and reading speeds are changed, thereby increasing the reading accuracy of the wobble signal.