A write-once type optical recording medium is provided, which is low-cost and capable of maintaining the recording and reproducing stability high while enabling the relative ratio of read power to write power to be set high.The high-speed write-once type optical recording medium 10 includes a recording layer 18 that is constituted by laminating first and second subsidiary recording layers 18A and 18B each having one type of metal, for example Al and Sb respectively, as the main component. In the optical recording medium 10 having such constitution, the ratio between write power Pw and read power Pr, Pw/Pr is set to a value in the range of 2.0 to 8.0. When the recording layer 18 is irradiated with laser beam with a wavelength of 200 nm to 450 nm and a write power Pw of 2.5 to 5.0 mW at a recording-transferring rate of at least 35 Mps, Al and Sb contained in the subsidiary recording layers 18A and 18B respectively are diffused and mixed by the irradiation to form a recording mark that has a low reflectance, has been transformed to a single layer, and has been changed irreversibly.