The invention provides a sputtering method which can efficiently form a film free from being affected by an insulation film formed on an edge area of a target. When reactive gas is guided into a sputtering chamber (11), a conductive target (41) which is opposite to a processing substrate S in the sputtering chamber is electrified. After plasma gas atmosphere is formed in the sputtering chamber, each target can be sputtered in order to form a specified film on the surface of the processing substrate. In the sputtering method, a sputtering power supply E for supplying power to the target is arranged for monitoring an accumulated power. When the value of the accumulated power reaches to a preset value, the guiding of the reactive gas is stopped and only sputtering gas is guided in to sputterthe target for a preset period of time.