The present invention provides a sp3-bonded boron nitride, represented by a general formula BN, having a hexagonal 5H or 6H polytypic form and having a property of emitting light in ultraviolet region. Its producing method comprises: introducing reaction mixed gas containing boron and nitrogen being diluted with dilution gas into a reaction chamber; and irradiating a surface of a substrate placed in the chamber, a growing surface on the substrate, and a growing spacing region about the growing surface with ultraviolet light to cause gas phase reaction, thereby generating, depositing, or growing the boron nitride on the substrate.