A substrate for an information recording medium, which is made of a glass or crystallized glass, (1) which has a region that has a spectral light transmittance of 50% or less converted in terms of a thickness of 2 mm in a wavelength range of 2,750 nm to 3,700 nm, (2) which shows a spectral light transmittance of 70% or less converted in terms of a thickness of 2 mm over whole wavelength range of 2,750 nm to 3,700 nm, (3) which contains an infrared absorbent that is a specific metal oxide and is for use in a perpendicular magnetic recording medium, (4) which is to be heated by irradiation with infrared ray and contains more than 200 ppm of water, or (5) which contains an infrared absorbent that is a specific metal oxide and is used as a substrate to support a multi-layered film including an information recording layer to be formed by sputtering after heating by irradiation with infrared ray, an information recording medium comprising a multi-layered film including an information recording layer formed on any one of the above substrates, and a process for producing an information recording medium.