To regulate the reflectance of a high-speed WORM type optical recording medium using a laser beam having a blue- or shorter-than-blue-wavelength laser beam to a desired value of up to 60%. The recording layer 18 of a high-speed WORM type optical recording medium 10 comprises laminated first and second sub-recording layers 18A, 18B mainly consisting of one kind of respectively different metals. When a blue-wavelength laser beam is applied to the recording layer 18, main-component metals contained in the first and second sub-recording layers 18A, 18B are diffused and mixed by the irradiation to form a recording mark having reflectance thereof irreversibly changed by the mixing. Since the recording layer 18 is sandwiched between first and second dielectric layers 20, 16, the reflectance of an unrecorded potion is regulated within a range of 5%-60% by adjusting the materials and thicknesses of the recording layer 18 and the first and second dielectric layers 20, 16.