This paper describes film deposition rates for rf planar magnetron sputtering when the magnetic field parallel to the target surface is varied. Magnetic‐field strength is a key parameter to control deposition rate in rf magnetron sputtering but applying a high magnetic field does not increase the deposition rate. Self‐bias voltage also decreases as the target magnetic field increases and plasma impedance involving the ion sheath region and glow discharge region is inductive. Plasma impedance measurements lead to the conclusion that a deteriorated deposition rate in the high magnetic field occurs due to decreased self‐bias voltage resulting from an increased sheath capacitance.