The invention provides metal powder constituted from metal particles. Each of the metal particles comprises a base particle having a surface and a metal material constituting at least the surface of the base particle. The base particle is subjected to a surface treatment with a fluorine type phosphoric acid ester. Further, the invention also provides an ultraviolet ray curable ink jet composition to be ejected by using an ink jet method. The ultraviolet ray curable ink jet composition comprises a polymerizable compound and metal powder constituted from metal particles. The metal particles of the metal powder are subjected to a surface treatment with a fluorine type phosphoric acid ester.