An optical recording medium on which information data is to be recorded and on which an n-th recording track is located at a distance from the (n-1)th recording track preceding the n-th recording track in a recording region which is narrower than the diameter of a spot of a light beam radiated on the recording area, with recording data obtained on logical processing with recording data recorded on the (n-1)th recording track being recorded on the n-th recording track for increasing the storage capacity of informer, ion data, is disclosed. A return beam of a light beam radiated across two neighboring recording tracks on the optical recording medium is detected by a detector having first and second light receiving sections having a boundary line extending parallel to the recording track of the optical recording medium for reading out the informer, ion recorded on the optical recording medium based on the level of a sum or difference signal of the output signals of the first, and second light receiving sections.