To provide a method and device for preventing approach of small drifting object, configured to prevent drifting articles such as a small craft or a driftwood from dangerously approaching a large vessel or the like, while securing safety of the small craft.

Bubbles B are released from a draft part of the large vessel 100 toward a sea surface W1, to form a water flow F1 toward a non-large vessel 100 (drifting articles such as small craft 101 or driftwood) near the sea surface W1. Near the sea surface, a water flow away from a non-approaching facility, in other words, the water flow from the non-approaching facility toward the outside and small article is formed, thereby preventing the small articles from approaching the non-approaching facility.