Herein disclosed are an apparatus and method for encoding a wobble signal to be recorded on an optical disc, and an apparatus and method for decoding a wobble signal read from the optical disc. The encoding apparatus performs a minimum shift keying modulation operation for a wobble signal to be recorded as physical address information on a writable optical disc, by adjusting a first frequency f1 and second frequency f2 of the wobble signal with coherence. Therefore, a peak point of the wobble signal is formed at a point of time that the frequencies change. The decoding apparatus band pass filters an analog wobble signal read from the optical disc, converts the filtered wobble signal into a digital wobble signal, detects a peak point of the converted digital wobble signal, outputs a peak detection signal with a level transition at the detected peak point, and detects/outputs original wobble data on the basis of the outputted peak detection signal. Therefore, the decoding apparatus is able to accurately decode the wobble signal in a simple manner.