Current port construction largely depends on manual work, and depending on the content of the work, skill is required and danger is involved. In addition, since the construction industry is a type of occupation in which the number of employees tends to fluctuate depending on the economic situation, it is quite conceivable that the shortage of workers will become a problem again. Under these circumstances, in order to improve the productivity and safety of the construction industry, it is necessary to standardize buildings, promote prefabrication and mechanization, reduce dangerous work, and eliminate reliance on workers' skills. It is important to develop construction technology. In the labor-saving construction technology currently under development in the field of harbor construction, labor-saving caisson manufacturing technology is progressing rapidly. Among these, precast caissons that unitize bulkheads with reinforced concrete slabs, panel system caissons that attach unitized composite slabs to the steel frame, and reinforcement unit construction methods in which reinforcing bars are pre-assembled on the ground and erected on top of the caisson have undergone demonstration tests. It is used locally. The development of construction methods for high-fluidity concrete, which can greatly reduce the labor for placing concrete, is also progressing. However, most of the labor-saving construction techniques are still under development. In order to disseminate labor-saving construction technology, it is necessary to promote further mechanization and automation of construction in the future.