In an optical information recording/reproducing apparatus, while a magnetooptical recording medium formed by stacking at least a recording layer, which consists of a perpendicular magnetization film for magnetically holding information, and a reproducing layer is rotated at a fixed angular velocity, a laser beam is applied to the medium from the reproducing layer thereby reproducing information held by the recording layer by transferring the information to the reproducing layer. First, information which indicates a relation of an optimum intensity of the laser beam in reproduction with respect to a radial position on the recording medium, previously recorded on the recording medium, is reproduced. Then, the intensity of the laser beam is adjusted on the basis of the information indicating the relation of the optimum intensity of the laser beam with respect to the radial position on the recording medium.