To obtain a vibration detector in which the number of components is reduced and whose mounting operation can be simplified by a method wherein a rectangular two-direction sensor is attached to a mounting frame or to a bowl.

A first spring 5 supports a bowl 10 attached to a mounting frame so as to be capable of vibrating the bowl 10 to the horizontal direction, and a second spring 5 supports the bowl 10 so as to be capable of vibrating the bowl 10 to the vertical direction. A first electromagnet excites the bowl 10 to the horizontal direction, and a second electromagnet excites the bowl 10 to the vertical direction. A vibration detector for an elliptical vibration parts feeder detects a vibration in the horizontal direction and that in the vertical direction. Then, a rectangular two-direction accelerometer P is attached to the mounting frame or to the bowl 10. When the vibration is sinusoidal, it is differentiated twice so as to obtain an acceleration. Since the horizontal direction and the vertical direction are at an identical frequency, the amplitude of both directions can be detected equally although a phase difference exists. By this constitution, the number of components of the vibration detector can be reduced, and its mounting operation can be simplified.