MARINE INFORMATION COLLECTION SYSTEM

An oceanographic information collection system includes an anchor (1) arranged on a sea bottom, an intermediate buoy (2) that is connected to the anchor (1) and floats in a sea, a mooring cable (3) connected at one end to the intermediate buoy (2), and an observation buoy (4) connected to another end of the mooring cable (3), wherein the observation buoy (4) includes a main body (41) whose longitudinal direction is arranged in a flowing direction of an ocean current, a specific gravity adjuster (42) that is arranged in the main body (41) and includes an expandable and shrinkable buoyancy bag (42a), an antenna (43) that is arranged on the main body (41) and transfers data, and an observation unit (44) that is arranged in the main body (41) and acquires prescribed oceanographic information, and the observation buoy (4) floats upward by expanding the buoyancy bag (42a) of the specific gravity adjuster (42), and the observation buoy (4) sinks by shrinking the buoyancy bag (42a) of the specific gravity adjuster (42) to be made to stand by in the sea. The buoy can easily float, sink and stand by in the sea.