There is provided an n type (100) oriented single crystal diamond semiconductor film into which phosphorous atoms have been doped and a method of producing the same. The n type (100) oriented single crystal diamond semiconductor film, characterized in that (100) oriented diamond is epitaxially grown on a substrate under such conditions that; the diamond substrate is (100) oriented diamond, a means for chemical vapor deposition provides hydrogen, hydrocarbon and a phosphorous compound in the plasma vapor phase, the ratio of phosphorous atoms to carbon atoms in the plasma vapor phase is no less than 0.1%, and the ratio of carbon atoms to hydrogen atoms is no less than 0.05%, and the method of producing the same.