This paper deals with an experimental study on the behavior of the Cavitation bubbles by using a flow visualization for the steady and unsteady flow. In the previous paper, experiments were carried out for various pressure changes of the upstream while keeping the downstream pressure constant. In this study, experiments were performed for various pressure changes which take the steady and unsteady flows at the downstream of a choke keeping the upstream pressure constant. The behavior of the cavitation bubbles is clarified with a camera and a high-speed video camera under three parameters: four kinds of the diameters d, two kinds of the lengths l, two kinds of the chamfered lengths s of the choke. As a result, three types of the sheet, bubble and cloud cavitations are able to observe in a long choke. The possessive region of each cavitation feature depends on d and s for a long choke even though the cavitation number is same value for the different d and s. The bubbles which occur in a choke repeat the growth, the division, the collapse at very short intervals.
