Deposition method and deposition apparatus

[Object] To improve step coverage of a coating film[Solving Means] A deposition apparatus that includes a first electrode, a second electrode, a first power supply source, a second power supply source, and a phase adjuster is used. The first power supply source includes a first high-frequency power source and a first matching circuit, the first high-frequency power source outputting first high-frequency power, the first matching circuit being connected between the first high-frequency power source and the first electrode. The second power supply source includes a second matching circuit that outputs second high-frequency power, the second high-frequency power having the same period as the first high-frequency power and being lower than the first high-frequency power. A second high-frequency power source is caused to output the second high-frequency power and the phase adjuster is caused to operate to provide a phase difference θ between a phase of the first high-frequency power and a phase of the second high-frequency power. A voltage value Vpp of the second high-frequency power and a capacitance value C1 of a first variable capacitor that correspond to the phase difference θ in a state where output impedance of the second high-frequency power source and load-side impedance connected to the second high-frequency power source match are detected. The voltage value Vpp and the capacitance value C1 are selected in combination in a predetermined range of the phase difference θ.