To provide a vibration level detection method and a vibration level detection apparatus capable of detecting a vibration size of an object timely and in real time.

A vibration level detection method or apparatus 1 for detecting a vibration level to be a vibration size of an optional portion of an object sets one of displacement, speed and acceleration of at least an optional portion of an object M in a vibration direction required to be detected as a first reference value (a) and finds out a vibration level r on the basis of the first reference value (a) and a second reference value b corresponding to a differential value or integrated value of the first reference value (a). Since the vibration level r is found out, the vibration size can be detected without requiring vibration of the object M for one period or more and the vibration level can be detected timely and in real time.