A method of selectively accessing a desired recording layer on a multi-layered optical disk is described. The multi-layered optical disk comprises a first recording layer (3) superposed on a first base plate (2), a second recording layer (4) superposed on a second base plate (2), and a spacer (5) of adhesive disposed between the first recording layer (3) and the second recording layer (4). Each recording layer (3,4) has an identification section (ID a , ID b ). Information is recorded on and/or reproduced from the recording layers (3,4) by a focused light beam. The method comprises changing the focus of the light beam and detecting zero cross points of respective focusing error signal S curves, each S curve corresponding to a respective recording layer, until the same number of zero cross points as an ordinal number of the desired recording layer is detected. The correct selection of the recording layer (3,4) is confirmed by reading an identification section (ID a , ID b ) thereof which stores its recording layer address.