A recording processing unit sets a track pitch narrower than a writing width of a recording element so that part of the recorded track overlapped with the unused track is overwritten, and continuously records information on a disk medium toward one direction in accordance with the track pitch. A first offset correcting unit reads a write/read offset from a storage table, in which the write/read offset is measured and saved in advance, and corrects the write/read offset in the state that a reading element is positioned at a target track. A second offset correcting unit corrects a write-once center offset, which is a positional deviation between a read center position of the reading element, which has undergone correction of the write/read offset by the first offset correcting unit, and a center position of an effective track width caused by write-once recording.