Abstract: A recording medium, a signal recording apparatus thereof, and a signal reproducing apparatus thereof, the recording medium having a recording area divided into sectors, each of which is composed of a plurality of frames with a predetermined bit length, wherein at least one of the frames contains a first synchronous pattern representing the length of the frame, a second synchronous pattern composed of a predetermined signal pattern that is not present in a signal pattern of user data and representing the period of the sector, identification data disposed at a predetermined position corresponding to the second synchronous pattern and identifying the sector, and error detection data for detecting an error of the identification data, and wherein each of the other frames contains the first synchronous pattern, the user data, and at least predetermined fixed data with which the second synchronous pattern is substituted and that is present in a signal pattern of the user data, the identification data, the error dete