A radiative cooling device including: a vacuum heat insulating container that has an opening portion, that is configured to house an object to be cooled therein and thermally vacuum insulates the object from an exterior thereof; a far-infrared radiator that is arranged between the object and the opening portion in the vacuum heat insulating container, that is thermally vacuum insulated from the exterior of the vacuum heat insulating container, that thermally contacts the object, and that radiates far-infrared rays in a wavelength range of from 8 μm to 13 μm; and a far-infrared transmitting window member that closes the opening portion of the vacuum heat insulating container and that transmits the far-infrared rays radiated from the far-infrared radiator.