The observation pier at Hazaki Oceanographical Research Station (HORS) is supported by steel piles that queue up in single row (partially double rows) to reduce the influence of sediment transport. Around piles, however, local and surrounding scour is caused in the surf zone because of wave breaking and nearshore current. In this report, the influence on the geographical features of sandy beach by the observation pier and the changes of coast uniformity in longshore direction are examined based on result of bathymetric surveys and aerial photographs around HORS. Following result of the surveys are used: 52 times of bathymetric surveys from February 1982 to August 2020 almost once a year, 31 times of aerial photographs from October 1947 to January 2020 that are bought from Geospatial Information Authority of Japan and ordered to aerial photography company, and a sonar sounding survey around piles in 2013.
The surrounding scour caused by the observation pier paling structure has extended within the range of about 30m, especially around the double rows paling part of the tip (P400 in the pier coordinate), the middle part (P200), and the movable bridge (P100), the scour has extended about 50m. The surrounding scour depth at the tip is about 1m, at the middle 0.75m, at the movable bridge about 0.4m. When the coast is eroded, the surrounding area of the observation pier tends to be eroded more. The longshore uniformity of coast is evaluated by space standard deviation along the coast except right under pier traverse line. Case of after storm, for instance 2007, the value of standard deviation grows which means uniformity is lost. The decrease in uniformity is canceled for about several years between P0-P400 where the wave breaking is frequently caused. In the offshore P400-P1000, the decrease in uniformity is not canceled for about seven years.
Contents of this report are useful to correspond to the request of observed data at HORS, moreover, becomes profitable to examine the influence on the topography with the structure constructed in the littoral drift region such as oceanic wind power generation pinwheels.

Key Words: Hazaki Oceanographical Research Station (HORS), bathymetric survey, surrounding scour, uniformity of coast in longshore direction, long-term beach evolution