A production method of a layered body having a single crystal layer comprising a group III nitride satisfying a composition shown by Al X Ga Y In Z N (wherein, X, Y and Z are rational numbers respectively satisfying 0.9 ≤ X ≤ 1.0, 0.0 ≤ Y ≤ 0.1, 0.0 ≤ Z ≤ 0.1, and X + Y + Z = 1.0) on a sapphire substrate by a metal organic chemical vapor deposition method, the layered body having an initial single crystal layer comprising the group III nitride and a second group III nitride single crystal layer; wherein said production method of the layered body comprises: a pretreatment step supplying an oxygen source gas to the sapphire substrate; a first growing step supplying an oxygen source gas with a raw material gas for growing said group III nitride crystal consisting of a nitrogen source gas and a group III raw material gas to the sapphire substrate after having carried out the pretreatment step, thereby growing the initial single crystal layer comprising the group III nitride satisfying said composition and containing oxygen in a concentration of 5 x 10 20 cm -3 or more and 5 x 10 21 cm -3 or less in a thickness of 3 nm or more and less than 15 nm on said sapphire substrate; and a second growing step of supplying the raw material gas without the oxygen source gas, or supplying the oxygen source gas in a less amount than the first growing step together with the raw material gas onto said initial single crystal layer, thereby growing the second group III nitride single crystal layer comprising the group III nitride satisfying said composition having reduced oxygen concentration than the initial single crystal layer, characterized in that said second group III nitride single crystal layer has a group III polarity plane as its surface, and in that at said pretreatment step, a temperature of the sapphire substrate is within a range of 850 °C or more and 1150 °C or less. a pretreatment step supplying an oxygen source gas to the sapphire substrate; a first growing step supplying an oxygen source gas with a raw material gas for growing said group III nitride crystal consisting of a nitrogen source gas and a group III raw material gas to the sapphire substrate after having carried out the pretreatment step, thereby growing the initial single crystal layer comprising the group III nitride satisfying said composition and containing oxygen in a concentration of 5 x 10 20 cm -3 or more and 5 x 10 21 cm -3 or less in a thickness of 3 nm or more and less than 15 nm on said sapphire substrate; and a second growing step of supplying the raw material gas without the oxygen source gas, or supplying the oxygen source gas in a less amount than the first growing step together with the raw material gas onto said initial single crystal layer, thereby growing the second group III nitride single crystal layer comprising the group III nitride satisfying said composition having reduced oxygen concentration than the initial single crystal layer, characterized in that said second group III nitride single crystal layer has a group III polarity plane as its surface, and in that at said pretreatment step, a temperature of the sapphire substrate is within a range of 850 °C or more and 1150 °C or less.