Abstract: An asymmetric excitation type magnetic device is provided with a composite magnetic body composed of a first magnetic layer having a relatively strong coercive force and a second magnetic layer having a relatively weak coercive force which layers are combined so as to have their respective magnetic anisotropy oriented in the same direction. To such a composite magnetic body are applied external positive and negative asymmetric magnetic fields in a specified order thereby to produce variations in magnetic flux due to an escpecially quick magnetization reversal and resultantly to generate steep pulse outputs across a detecting coil.