Method for producing group iii nitride crystal, group iii nitride crystal, semiconductor device and apparatus for producing group iii nitride crystal

Provided is a method for producing a group III nitride crystal, which exhibits excellent reactivity and operability, and wherein a by-product containing a halogen does not have an adverse effect on crystal formation. A method for producing a group III nitride crystal, which is characterized by comprising a group III nitride crystal production step for producing a group III nitride crystal by reacting a group III metal element, an oxidizing gas and a nitrogen-containing gas with each other.