Provided are an optical disc recording device and a recording signal generating device which enable to correct displacement between a reproducing position of a reproduction signal from a concave-convex mark preformed in an optical disc, and a recording position of second information to be recorded in synchronism with the reproduction signal, and stably and speedily record the second information. A digital signal processor (202) specifies a reproducing position in the concave-convex mark, using a reproduction signal and a channel clock. A recording signal generator (211) generates a recording signal alternately including a plurality of additionally recordable data, each of which includes second information and has a predetermined length, and a plurality of dummy data. A recording position controller (110) detects a recording position displacement amount representing a displacement amount between the reproducing position and a recording position of the additionally recordable data, using the reproducing position and the reading signal. A recording length adjustor (208) increases or decreases the recording length of dummy data in accordance with the recording position displacement amount.