A non-linear electromagnetic vibration device including a first vibration part and a second vibration part. A non-linear bellows plate spring set is connected between the first and second vibrating parts. Each spring set is composed of sequentially coupled bellows plate springs, and each plate spring is elastic according to a predetermined particular waveform and has a plate structure of a predetermined shape. The waveform is selectable among many including portions of an exponential curve. The plate structure of each spring is rectangular with an edge which is straight, convex, or concave in contour. The first vibration part of the device is rigidly connected to a corresponding section of each spring set and the second vibration part of the device is coupled to a different or second area of each spring set. An electromagnetic core and armature of an electromagnetic source and respectively included in a different one of said first and second vibration parts, and stable reciprocating structural components each of a parallelogram shaped configuration are formed. Harmonic resonance frequency conversion can be obtained conveniently via mechanical adjustment of the number of plate springs in each sectionalized waveform plate spring set.