As the law for promoting offshore wind power was implemented in April 2019, it is expanding the submarine ground survey market for the construction of offshore wind power generation. In general ground surveys, suspension PS velocity logging using boring holes has been used to measure the S-wave velocity required to grasp the distribution of the support layer of the ground or engineering foundation depth at sea. However, the offshore wind power generation (implantation type) targets sea areas with an average annual wind speed of 7 m/s or more and a water depth of about 10 to 40 m, and boring in harsh environments is not easy. Therefore, we have developed “Offshore Microtremor Array measurements” for the purpose of grasping S-wave velocity structure in short time without the need for boring survey. In this paper, after showing an overview of the development of this method, we then show the application examples and characteristics of offshore microtremor obtained from offshore microtremor array measurements conducted at various sites. The S-wave velocity structure estimated by microtremor array measurements is consistent with PS-velocity logging and multi-channel seismic reflection profiles, indicating the applicability of microtremor array measurements to offshore ground survey.