Nitride single crystal

Patent Pending PROBLEM TO BE SOLVED: To provide a method for producing a nitride single crystal by an ammonothermal method, by which both of a fast growth rate and high crystal quality can be achieved. ; SOLUTION: The method for producing a nitride single crystal from a nitride polycrystal by an ammonothermal method is carried out by using at least one kind of nitride polycrystal as a raw material 6 in the presence of ammonia in a supercritical or subcricital state in a corrosion-resistant autoclave 3, and adding at least one kind of acidic mineralizer to the ammonia.